By Matthew Wandell

Photos by Richard Ross

One of my first experiences with the Tuka Anthias (Pseudanthias tuka) was seeing a shoal of these bright purple fish at a local wholesale facility. They certainly didn’t look any different than all the other Anthias in the tanks there, yet I had read many books and articles that described how difficult these little beauties were to keep in captivity. I wisely avoided purchasing them at the time, but a friend of mine bought some a short time later. He was an experienced aquarist with several other beautiful Anthias in his tank, and he even got them to eat frozen copepods within just a few days of adding them to his system. However, frozen copepods were about the only thing they would eat, and they slowly but surely lost weight. He tried in vain to keep them alive in his large reef tank and would even drive home from work every day at lunch to feed them. Sadly, they all died of extreme malnutrition after about 6 months in his tank. To add insult to injury, the amount of food he was adding to his tank had created a bit of an algae problem. The more I read about them the more it appeared that this was the inevitable fate of these beautiful but impossible fish. Knowing this, when the public aquarium I work at received a dozen Tuka Anthias I was pretty skeptical that we could handle the challenges of keeping them healthy in the long term.

After two and a half years of keeping them, I’ve learned quite a bit about the Tuka Anthias firsthand. I don’t consider myself a fish or Anthias “expert”, but I can recount what has worked for me in keeping these fish. Hopefully more success stories will expand the body of knowledge of their husbandry. I have always had strong views about difficult or “expert only” animals and how to respond to questions about how to keep them. My feeling is that we should give everyone the very best chances of success by supplying them with the most detailed husbandry advice available from the rare instances of success. The advice of some experienced aquarists might be something like: “Leave them in the ocean!” The unfortunate reality is that no amount of wishing an ill-advised purchase wasn’t made will make it so. While I certainly understand this sentiment, in my opinion it does little to dissuade a potential buyer from purchasing the animal and certainly does not help him care for it properly after he does. There will always be hobbyists who are determined to try to keep difficult animals despite all the advice in the world telling them otherwise. My hope is that with a better understanding of the challenges that lay ahead a person contemplating buying a difficult animal will have better prepared themselves to care for it.

Keeping Anthias

If you’re even considering keeping Tuka Anthias, hopefully you’ve already cut your teeth on some of the easier to keep Anthias species and are already a bit familiar with the behavior and care of the genus in captivity. The biology and life history of Anthias has been covered extensively in past literature. The majority of fishes that we call “Anthias”, including the Tuka Anthias, belong to the genus Pseudanthias. All Pseudanthias spp. are protogynous sequential hermaphrodites that live in mixed sex shoals in areas of high current and plankton availability (Michael, 1998). In captivity these traits have important considerations for their care. Anthias can be kept in small shoals as long as adequate space is provided. In the absence of males, large females will change sex (and color) to become male and aggressively assert their dominance over nearby females and other males. In general, if Anthias are purchased as males it is advisable to add only one per tank, unless the tank is very large. Large males generally tend to ship and acclimate more poorly than small females, and if they do arrive safely they may spend most of their time chasing and harassing smaller individuals. You may find it simpler to just purchase all females and let one or several (more on this later) turn into males all on their own. All of the Pseudanthias spp. are zooplanktivores that swim in open water in search of fish eggs, small crustaceans and other tiny animals, and thus appreciate a lot of swimming room and frequent feedings. Every aquarium is different, so there aren’t any hard and fast rules on how many individuals are “okay” for a given tank volume. In general, minimal amounts of live rock with ample swimming space will suit an Anthias just fine, while a tank crammed with live rock and/or coral may make an Anthias a bit reluctant to swim about and feed. Feeding frequency depends a lot on the size and species of the individual fish, but in general, two to three times a day as a minimum is recommended.

There is great variability within the genus in terms of aquarium suitability and care. Some of the more common and easier Anthias species to acclimate to captivity are the Lyretail Anthias (P. squamipinnis and P. cheirospilos). The vast majority of Lyretail Anthias individuals will readily eat frozen or flake food within days of being placed in a controlled environment and thrive for years in aquaria. On the other end of this spectrum are species such as the Tuka Anthias that often refuse to thrive, even in the hands of dedicated aquarists. An online search at discussion forums highlights this frustration:

“They will die! Tukas’ have a dire survival rate in Home Aquaria and should be left in the ocean.”
“Gorgeous, but unkeepable.”
“Pretty much everything said here is the general consensus about these fish. You buy them, they die.”
“I’ve yet to hear a long term successful tuka story… I’d avoid these.”

So what makes Tuka Anthias so much more delicate than the more durable species like the Lyretail Anthias? I like to describe the feeding strategy of this fish as “Microscopic Tunnel Vision”: If a food item is bigger than about 1-2 millimeters, it might as well be made of cardboard as far as Tuka Anthias are concerned. While many Anthias will readily eat something as large as a whole frozen mysid, it is highly unlikely that a Tuka Anthias will accept a food item of this size, even if the food is alive. Over time they may begin to learn differently, but during the first several months it is a good bet to assume they will ignore most normal size aquarium food.

Identification

The Tuka Anthias (P. tuka) can be easily distinguished from most other Pseudanthias species by its vivid purple coloration. Females of the Tuka Anthias are mostly purple but sport yellow stripes on the top and bottom of the caudal fin and a thin yellow stripe that runs along the back from behind the head to join the yellow stripe at the top of the caudal fin. As females mature into males they undergo a chromatic and morphological transformation. Their snout becomes pointed, the caudal fin develops filaments on the tips, and the dorsal fin becomes wider and more angled towards the tail. The yellow stripe along the back changes to purple and a red spot develops at the base of the back of the dorsal fin. The area underneath the mouth changes from purple to a bright yellow color. There is a closely related species called the Pascalus Anthias (P. pascalus) which is sometimes confused with the Tuka Anthias. The Pascalus Anthias sports the same vivid purple coloration as the Tuka Anthias, but the two species can be easily distinguished if you know what to look for. Juveniles and females of the Pascalus Anthias are completely purple on all areas of the body and lack the yellow stripe that distinguishes the female Tuka Anthias. Similarly, males of the Pascalus Anthias are usually entirely purple and always lack the yellow chest and snout that distinguish males of the Tuka Anthias (Myers, 1999). Another similar looking species is the Evans’ Anthias (P. evansi). Evans Anthias share the bold purple coloration of Tuka and Pascalus Anthias, but both sexes of the Evans Anthias always have an entirely yellow dorsal and caudal fin. However, there are geographical variations or subspecies of these Anthias that show different color patterns. Some male Pascalus Anthias develop a yellow tail at sexual maturity (Fishbase, pers. observ.), and Tuka Anthias from the reefs of the Rowley Shoals have a yellow stripe along the top edge of the dorsal fin (Kuiter, 2004). If all this is not confusing enough, these fish are interchangeably called Purple Anthias, Queen Anthias, or Purple Queen Anthias by wholesalers and retailers…is anyone starting to feel like learning the proper Latin names might be a bit simpler?

Fortunately, Tuka Anthias handle shipping and transport relatively well and are fairly resistant to the most common fish parasites. Tuka Anthias are commonly found in relatively shallow water (less than 20m) and so do not typically suffer from swim bladder issues resulting from improper decompression that affect so many other species. The same rules for selecting other marine fish apply to Tuka Anthias; when observing newly collected specimens look for individuals that are actively swimming about looking for food and show no signs of disease. The eyes and fins should be clear, breathing should be relaxed, and any scratching on rocks or sand should be a cause for concern. They are easily bullied by other fish, such as clowns, tangs, dwarf angels, or small wrasses. Ideally they would be held in tanks containing very peaceful species such as dartfish, gobies, or other small Anthias or Chromis. Tuka Anthias individuals that persistently hide in the rocks or in a corner of the tank may need to be moved to a tank with less aggressive fish. If healthy Tuka Anthias are given ample swimming and hiding room and a low stress environment to relax in they should begin swimming in the open and eating live baby brine shrimp or frozen copepods within a few days. Particular attention should be paid to the shape and musculature of the fish. The belly should be full and the area behind the eyes should not appear pinched. In general, all Pseudanthias spp. are fairly resistant to common fish parasites, but if Tuka Anthias do show signs of disease they can be safely treated with chloroquine phosphate, praziquantel, cupramine, or hyposalinity.

To quarantine or not?

Newly imported Tuka Anthias will be physically stressed and weakened by the time they arrive at a retailer after weeks of being bagged, shipped, and underfed throughout the chain of custody from ocean to aquarium. The level of care they are immediately placed into by the aquarist is critical at this time. The most important parameters during the first few months of captivity are to provide food virtually all day long, keep water quality high, and eliminate stressors such as aggressive tankmates or heavy traffic around the tank. This may be best accomplished in a dedicated quarantine tank. A 75-90 gallon tank will be fine for a grouping of 10-15 small individuals during quarantine. The tank and life support system do not need to be elaborate. For Tuka Anthias I use a bare tank with a pile of mature live rock, a heater, and a few powerful airstones. One distinct advantage to this type of setup is that since there is no mechanical filtration, you can put an excess of live food in the tank to ensure the fish can eat all day long. The flow created by the airstones ensures that food will remained suspended in the water where the Anthias will eat it. The live rock will keep ammonia and nitrite at an undetectable level, and the airstones keep dissolved oxygen high. Whether you set your quarantine tank up this way, or with a wet/dry filter, fluidized bed filter, algal turf filtration, protein skimmer, activated carbon, etc., keep in mind that frequent feeding with zero ammonia/nitrite and high oxygen should be the areas of most concern. I keep an ammonia alert badge in the tank to alert me to the presence of the slightest bit of ammonia. Siphoning the bottom to remove waste and performing large (50% or more) water changes are a frequent routine during this time. A small mechanical power filter used for a few hours can be very effective in clearing the water at the end of every day, but it should be cleaned out frequently. Lighting is generally irrelevant, but these fish will do fine with standard fluorescent bulbs on a 12 hour cycle. The tank should be covered, or filled to 6″ from the top, to prevent leaping fish from getting out of the tank. If there are any other tankmates at all during quarantine they should be small peaceful dither fish such as dartfish or Chromis. Wrasses, tangs, angels, and aggressive Anthias are likely to harass or otherwise stress Tuka Anthias. Among the Pseudanthias species I have kept with Tuka Anthias are P. dispar, P. lori, and P. ventralis; none of these caused problems associated with aggression. Larger or more aggressive Anthias such as P. pleurotaenia, P. squamipinnis, P. randalli or P. parvirostris may harass the Tuka Anthias in smaller tanks.

It’s feeding time again!

The most difficult hurdle in keeping Tuka Anthias alive is to ensure a nearly constant supply of food of a very small size throughout the day. Since they only accept such small foods, simply tossing food in 2 or 3 times a day is insufficient to keep these fish thriving long term. I would strongly advise anybody planning on keeping Tuka Anthias to find a way to feed these fish 6-8 times a day in order to keep them well fed. Most aquarists (even ones at public aquariums) don’t have the time to manually feed their tank 6-8 times a day, but fortunately there are ways around this (more on this later). During the first few weeks of captivity Tuka Anthias are likely to only eat enriched baby Artemia and/or copepods, and dripping these foods into the tank on a continuous basis should be considered a necessity to keep them well fed. Cultures of Daphnia, live or whole frozen copepods, and newly hatched Artemia will assist in feeding during this critical period. After a few weeks Tuka Anthias should become a bit more used to the feeding routine and start to accept other food. At this point it’s a good idea to start experimenting with anything and everything that you think the fish might eat. Don’t hesitate to use “no-no” foods–the first priority is to get these fish to eat anything at all, then start worrying about nutrition and long term diet later. Capelin eggs can be purchased from some Asian supermarkets in the form of “Masago”, although the eggs have dyes and salts added for use as a sushi product. Masago is suitable as a fish food if it is thoroughly rinsed and strained, and Tuka Anthias may begin eating capelin eggs within a few weeks. Adult Artemia is easily enriched to improve its nutritional value by adding liquid or powdered enrichment products to the culture vessel for a few hours before feeding to the fish, and few fish will be able to resist eating them. Another food that may be accepted by Tuka Anthias is very finely chopped clam meat. This can be prepared by raking frozen clam tongue across a fine cheese grater and rinsing and straining the resulting “mush” in a baby brine shrimp net. This can be done with frozen squid, scallop, krill, or mysis shrimp as well but clam seems to work particularly well. The trick here is to remember to keep the particles very small, about the size of grains of table salt, and to be creative–the more variety you can offer the better. If you live near the ocean, or even near a clean lake, try trolling a plankton net through the water at night and see what you come up with. Small tidepools are usually teeming with small crustaceans and some of these can be easily cultured. Live foods that are more familiar to freshwater fish keepers can come in handy too; microworms, mosquito larvae, and Daphnia may be accepted by Tuka Anthias. There are a huge variety of small planktonic foods available at local fish stores that would be great to experiment with as well. The long term diet I offer the Tuka Anthias under my care is approximately equal parts live enriched (Algamac Enhance for 4 hours prior to feeding) Artemia (adult and newly hatched), capelin eggs, frozen copepods (Cyclop-eeze and Arcti-pods), chopped frozen mysis (Piscine Energetics and Hikari brands), and chopped frozen clam tongue. Now that they are healthy and well fed they can occasionally endure a few days of light feeding or even no feeding at all without much harm.

In order to feed a tank 8 times a day I use a custom built automatic feeder that adds live Artemia and frozen copepods to the aquarium. The automatic feeder consists of an acrylic “Commercial Brine Shrimp Hatcher” cone (Aquatic Eco-Systems Part BS6) filled with system water that gravity drains into the aquarium at regular intervals. A programmable automated ball valve (Gilmour Water Timer Part 9408GF) opens up for 60 seconds every hour eight times per day to drain the water from the cone into the tank. The feeder is filled with approximately 5 gallons of tank water every morning and live enriched adult and baby Artemia are added to the feeder, along with a small amount of live phytoplankton (Reef Nutrition PhytoFeast Live) to keep the Artemia “topped up” on food. A small air line is inside the cone to keep the mixture aerated and stirred. This is a rather expensive and bulky automatic feeder setup, but it is low on maintenance and easy to work with. Recently I have switched to using a peristaltic pump instead of the automated ball valve in order to add food in smaller amounts more frequently. This also allows me to place the automatic feeder below aquarium level if I desire. Smaller and less expensive units could easily be built to fit underneath a tank stand or inside of a sump; the only limitation is the creativity of the designer.

Creating a Tuka Anthias shoal at home

It may take anywhere from 3 to 6 months for Tuka Anthias to become fully acclimated to captivity and eat a variety of different foods consistently. Once they are settled in to their new homes and have fattened up a bit, these fish are relatively durable and easy to keep as long as you feed them very often. If there are no males present, and sometimes even if there are, females may begin changing sex into males if they are in good condition. The earliest signs of this occurring will be on the snout of the fish in the largest or most aggressive females, accompanied by increased aggression and dominant displays to smaller individuals. Males have an extended upper lip that is one of the first noticeable signs of sex change, followed by change in body color and fin shape. After a few weeks the sex change should be complete, but sometimes it can be interrupted or slowed by the presence of other males. In many Pseudanthias spp. the males can become very aggressive and will prevent other females from transitioning into males. The Tuka Anthias is rather wimpy in this regard; one of my biggest problems with these fish is keeping them all from turning into males! Despite a shoal of nearly all apparent males, they seem to get along well and there are clearly “supermale” individuals with brighter colors that dominate the group. In most cases this amounts to flashing fins and brief chases without any real damage to the subordinate fish.

When kept in shoals all of the Pseudanthias spp. should be given ample swimming room to reduce instances of aggression. I like the trend of less live rock and more open water that is currently the “it” look in modern reef aquariums, and your Anthias will like it too! Tuka Anthias are found on reef slopes in shallow water, so they are perfectly suited to a typical coral reef aquarium with high light, high flow, and temperatures in the range of 75-82 degrees F. Although Tuka Anthias will not directly harm any invertebrates, their need for frequent feeding has obvious impacts on water quality and the species of corals they can be kept with. Any reef aquarium designed around these fish should take these considerations into account when planning life support design and coral selection. I hope this article has inspired you to try to keep the Tuka Anthias in a very carefully planned and designed aquarium, and am always interested to hear experiences or answer questions about this species’ care. I can be reached at [email protected]for any further questions or comments.

References

www.fishbase.org

Kuiter, R. H., 2004 Basslets, Hamlets, and their relatives: a comprehensive guide to selected Serranidae and Plesiopidae. TMC Publishing, Chorleywood, UK.

Michael, S. W., 1998. Reef Fishes: a guide to their identification, behavior, and captive care. TFH Publications, neptune City, NJ.

Myers, R.F., 1999. Micronesian reef fishes: a comprehensive guide to the coral reef fishes of Micronesia, 3rd revised and expanded edition. Coral Graphics, Barrigada, Guam.