Posted by TFH Magazine in Tropical Fish Hobbyist Blog on February 27, 2013 at 10:43 am
By Bob Fenner
In the March 2012 issue, Bob Fenner offers his recommendations to create a compatible mix of livestock together for a nano tank. A major concern is including species that won’t chemically harm the tank.
There are likely more cases of life in the shallow seas having chemical and physical communication than not. Particularly where reef life is sedentary, slow moving, or stuck in place (versus fishes which are able to swim away) organisms have various mechanisms to keep their turf. Some of these interactions are of more than academic interest to us as aquarists. Bad mixes will begin warring with each other, even to the extent of poisoning others and causing the collapse of the entire system. A prime example are the animals collectively called “corals” by most hobbyists, which can and do sting, poison, and attempt to eat each other competitively. However the cnidarians don’t have a monopoly on such subterfuge. Most all colorful, slow or non-moving sea life, including algae, nudibranchs, several sea cucumbers, and many others have something that prevents their displacement or consumption. Here are just a few examples:
Caulerpa is a genus of macroalgae that has been used in refugiums for the purpose of nutrient export. When carefully maintained, the algae can be beneficial. However, this genus can be toxic if grown too fast in too high a quantity, in the absence of decent filtration and maintenance. Its species are not to be trusted in small volumes.
Tube anemones are bad “shedders” of stinging material, and should be kept with only organisms it is known to live with while causing no harm in the wild. Within the pet-fish trade worldwide the most common species offered is Cerianthus membranaceus from the Philippines, but all are too toxic to mix in a community setting.
Nudibranchs are known to be toxic, but one in particular is especially dangerous in a community setup. Phyllodesmium hyalinum is a solar powered nudibrach, as it contains zooxanthellae. It can can take out a small system if it dies and dissolves without detection.
The Australian sea apple (Paracucumaria tricolor) is generally imported from the Philippines and Indonesia. It’s a killer that I’ve seen take entire systems with it eviscerating or otherwise falling apart.