In Praise of Fish Oil

Fish oil is an important part of Paul B’s fish feeding regimenHobby pioneer Paul “Paul B” Baldassano has some strong opinions on what types of foods are best for fish, formed over his many decades of involvement in the marine aquarium hobby. Somewhere near the top of his list is fish (or krill) oil. He explains exactly why in the following excerpt from the third chapter of his book The Avant-Garde Marine Aquarist: A 60-Year History of Fishkeeping:From Chapter 3: Keeping Fish Healthy Oil, in my opinion, is one of the most important things you can feed to fish. No, not Oil of Olay or olive oil, but fish or krill oil. I take it myself every day, but not too much, as I don’t want to resemble my old flounder-faced girlfriend. In the sea, fish get a large percentage of their diet from pure fish oil.

Why Isn’t Cryptocaryon irritans a Major Problem for Wild Marine Fish?

Whitecheek Tang (Acanthurus nigricans) afflicted with Cryptocaryon irritansDuring yesterday’s Thanksgiving get-together, which my wife and I host for my side of the family every year, a teenaged nephew asked me about marine ich (Cryptocaryon irritans)—the one fish disease he’s heard something about from a friend who keeps saltwater tanks. As I explained the parasite and its lifecycle and why I think it’s so important to quarantine new specimens, he asked, “If ich spreads so easily, why aren’t all the fish in the ocean infected?” Thrilled that, for once at least, I could offer my curious young nephew something akin to wisdom, I explained that the following factors help keep ich infections at a manageable level in wild fish populations:The vastness of the ocean Even though coral reefs appear to be bristling with fish, the density of the fish population relative to the volume of the ocean is, if you’ll excuse the pun, a mere drop in the bucket. Remember, during the tomite, or theront, stage of the Cryptocaryon lifecycle, the free-swimming parasites must find a host fish to attach to and feed upon within a relatively short period or they die. In the vast ocean, with its limitless water volume and powerful, dynamic currents, only a very small number of tomites ever succeed in locating a host. On the other hand, in a closed aquarium system, even if the actual number of fish specimens is fairly small, the population density is still extremely high relative to the volume of water. Of course, the density of host-seeking parasites relative to the water volume is also very high.

Some Subtle Signs that a Fish is Sick

I’ve kept multiple copperband butterflyfish (Chelmon rostratus) in my reef over the yearsMost marine aquarium hobbyists learn quickly to identify common warning signs of ill health in fish—white spots, excessive mucus production, bulging eyes, frayed fins, etc. But sometimes ailing fish exhibit much more subtle symptoms that are evident only to someone with powers of observation honed by many decades of experience. In the following excerpt from his book The Avant-Garde Marine Aquarist: A 60-Year History of Fishkeeping, hobby pioneer Paul “Paul B” Baldassano demonstrates how things with fish aren’t always what they seem:A copperband conundrum Recently, I was in a large LFS in New York. My mother-in-law is in a nursing home nearby, so I go there often. This store is very old, and I even helped start their saltwater tanks in the early 70s. They had a tank of about five copperband butterflies, and they were kind of cheap—like $20.00, which is a great price for copperbands.