compatability with chili coral

Dear Duno:

The chili coral is a nonphotosynthetic soft coral with very little stinging ability, and it is therefore generally safe to keep in the same aquarium with seahorses. The larger seahorse species such as Hippocampus erectus, H. barbouri, H. comes, H. reidi, and H. kuda would all be fine in a tank with chili coral.

However, I would not recommend trying a chili coral in your dwarf seahorse tank, sir, not so much out of concern for its stinging ability but rather because of the chronic problem dwarf seahorse tanks have with hydroids. Sooner or later hydroids will appear in any marine aquarium that is receiving regular feedings of rotifers, copepods, or baby brine shrimp or plankton suitable for filter feeding invertebrates. It’s inevitable because they can can gain entry into the aquarium in many ways. For example, they are notorious hitchhikers. Both the colonial polyp stage and the free-swimming micro-jellies can thumb a ride on live rock, macroalgae, hitching posts, sand or gravel, specimens of all kinds, or within so much as a single drop of natural seawater (Abbott, 2003). Beware of fuzzy looking seashells! Very often hydrozoans come in on the shells of the hermit crabs or snails we purchase as aquarium janitors (Abbott, 2003). Or they may be introduced with live foods, or even among Artemia cysts, in some cases it seems. They can even be transferred from tank to tank in the aerosol mist arising from an airstone or the bubble stream of a protein skimmer.

Hydroids are insidious because they start out so small and insignificant, yet spread so quickly under ideal conditions (e.g., a nursery tank or dwarf seahorse tank receiving daily feedings of Artemia nauplii). Many species can spread asexually by fragmentation as a microscopic speck of the parent colony. All of the troublesome types have a mobile hydromedusae stage, which look like miniscule micro-jellyfish, and can spread sexually in this way as well (Rudloe, 1971). The mobile medusae swim about with a herky-jerky, pulsating motion and are often mistaken for tiny bubbles due to their silvery, transparent, hemispherical bodies (Rudloe, 1977). These tiny jellies often go unrecognized until they begin to settle and are discovered adhering to the tank walls. They will have a large "dot" in the middle of their bodies and smaller ones at the base of their nematocysts (Abbott, 2003). Both the polyp stage and the medusa stage sting (Rudloe, 1977) and are capable of killing or injuring seahorse fry. Multiple stings can kill the babies outright, but they are often only injured by the nematocysts, which damage their integument and leave them vulnerable to secondary infections. Many times it is a secondary bacterial or fungal infection that sets in at the site of the injury which kills the fry.

Once they find their way into a dwarf seahorse setup or nursery tank, hydroids can explode to plague proportions very quickly because conditions are ideal for their growth: perfect temperatures, an abundance of planktonic prey that is renewed every few hours, and a complete absence of predators.

My point is that your dwarf seahorse tank is going to experience an outbreak of hydroids at some point, Duno, and when that happens you are going to need to treat your dwarf tank with Panacur (fenbendazole) in order to eradicate the hydroids. Unfortunately, fenbendazole is also deadly to polypoid corals and your chili coral would not withstand the regimen of Panacur. Sooner or later you are going to be faced with the problem of hydroids, and that would put you in the difficult position of either sacrificing your chili coral or sacrificing the dwarf seahorses.

Secondly, sir, if you have a thriving colony of 20 dwarf seahorses you probably don’t want to introduce a specimen that feeds on newly hatched brine shrimp and that will make it more difficult for you to maintain an adequate feeding density of Artemia nauplii in your dwarf seahorse tank by competing with them for their planktonic prey.

In short, feel free to try a chili coral in a tank with any of the greater seahorses, but I would not take the risk of including such a coral in your dwarf seahorse setup.

Best of luck with your pint-size pigmy ponies, Duno!

Respectfully,
Pete Giwojna