by Saltwater Smarts | Jan 29, 2016 | Fish, Invertebrates, Opinion, Reef, Science
Porcupine pufferfish (Diodon holocanthus)Circumtropical in distribution and ascribed more common names than one can possibly keep straight (spiny puffer, porcupine puffer, porcupinefish, longspined porcupinefish, and balloon porcupinefish, to list but a few), Diodon holocanthus can be a worthy, very pet-like aquarium candidate. This species does, however, have certain non-negotiable needs to be met if it is to live a long, healthy life in captivity. Physical traitsD. holocanthus has a robust, vaguely (American-style) football-shaped body with prominent, bulbous eyes and numerous elongated spines covering its body. These spines normally lie flat against the fish, but when threatened or harassed, it can swallow water or air, causing its body to inflate to nearly twice its size and its spines to stand erect (thus resembling what everyone else in the world calls a football with spikes all over it). The teeth are fused together to form a beak-like structure. Not the most colorful fish in the sea, D. holocanthus typically has a creamy to light-brown base color with dark-brown mottling and spots. by Saltwater Smarts | Jan 23, 2016 | Fish, Reef, Science
While a fish might seem to have an exclusive diet, they’ll often chow down on “off-menu” offerings, as wellCarnivorous fish eat meat, herbivorous fish eat algae/plants, and omnivorous fish eat both. That’s the order of things, and any fish we buy for our aquariums should fit nicely into one of these categories so we know exactly what to feed it, right? Well, if that’s the case, why on earth do my blue-chin triggers (Xanthichthys auromarginatus)—carnivores by nature—always beat my tangs and foxface to the dried algae sheets I offer and actually eat the lion’s share? After all, FishBase describes X. auromarginatus as “[forming] loose aggregations a few meters above the bottom where it feeds on zooplankton, particularly copepods.” Nowhere in this statement do you see, “Oh yeah, and it likes to tear into algae from time to time, too!”On the flipside of the coin, just as my triggers seem to enjoy ordering “off-menu,” my herbivorous yellow tang (Zebrasoma flavescens), Atlantic blue tang (Acanthurus coeruleus), and one-spot foxface (Siganus unimaculatus) will greedily gobble up any meaty items that they can fit in their mouths as well. What gives? by Saltwater Smarts | Jan 18, 2016 | Fish, Invertebrates, Reef, Science
Sometimes external stressors can cause aggression amongst tankmatesFish wounds and injuries can result from a variety of different influences, with tankmate aggression being among the more commonplace. Unfortunately, hobbyists don’t always recognize this problem right away when it manifests itself. Jay Hemdal, Curator of Fishes and Invertebrates for the Toledo Zoo, explains why in the following excerpt from his book The Salt Smart Guide to Preventing, Diagnosing, and Treating Diseases of Marine Fishes: Tankmate aggression This is a potential issue in any marine aquarium that houses more than one fish. In the most serious instances, where the aquarist severely underestimates the ability of one fish to injure another, aggression actually takes the form of predation. There are also cases of fish living peacefully side by side for years and suddenly beginning to fight. Home aquarists are often in denial that any aggression is taking place because, with the exception of the most severe cases, it is very difficult to “catch them in the act.” Take, for example, a case of minor aggression where one fish is “tagging” another one (damaging a fin with a bite) at a rate of once or twice a day. What are the chances that an aquarist is going to see the aggressive act? by Saltwater Smarts | Jan 15, 2016 | Fish, Invertebrates, Reef, Science
Rock Beauty Angelfish (Holacanthus tricolor)On one of my earliest dives down in the Florida Keys back in the 1990s, a gorgeous yellow and black angelfish caught my attention as I drifted over a section of reef. In my mind’s eye, I envision the angel hovering boldly above a large barrel sponge, but I can’t be sure whether that’s actually how it happened or just an idyllic memory. In any case, I was taken with its distinctive appearance and wondered whether it might make a good aquarium candidate. As anyone familiar with the fauna of the tropical western Atlantic has already guessed, the angel I saw back then was a rock beauty (Holacanthus tricolor)—a species that, unfortunately, tends to fare poorly in marine aquaria and is generally best left to advanced fishkeepers or, better yet, in the ocean where it can beguile other divers. I’ll get into why in just a moment.Physical traits H. tricolor is laterally compressed (flattened from side to side) and, in typical angel fashion, sports a sharp, backward curving spine on the gill cover (operculum). As alluded above, this species is yellow on the anterior portion of the body and on the caudal fin and black from behind the gills to the caudal peduncle (base of the tail). The margin of the anal fin, the edge of the operculum, and the opercular spine are orange. by Saltwater Smarts | Jan 5, 2016 | Fish, Reef, Science
Cleaner Wrasse (Labroides dimidiatus) offering some “dental care” to a potato grouper (Epinephelus tukula)The introduction of Labroides spp. cleaner wrasses to marine aquarium systems is generally ill-advised. Though some hobbyists report success in keeping these obligate cleaners long term, the vast majority of specimens entering the market are doomed to perish prematurely from starvation. Nonetheless, despite their abysmal captive survival rate, people continue to buy these wrasses, likely owing to some persistent misconceptions surrounding them. Among these myths are:1. If the wrasse can’t get enough to eat by cleaning, it will learn to accept other foods First off, there’s no if about it—a cleaner wrasse kept in a home aquarium cannot sustain itself long term by cleaning its tankmates. After all, in your average home system, there are going to be very few clients to service and they likely won’t have much of a parasite load or dead tissue to offer. So, if the wrasse doesn’t learn to recognize aquarium fare as edible, it’s destined to starve
