Aggressive Fish | The Importance Of Keeping A Spaz Tank
You'll often read about why it is so important for fish keepers to have a hospital tank on hand for sick fish, but it is much rarer for people to impress the importance of a spaz tank on new fish keepers. I use the term 'spaz' to refer to 'spazmodic', as in fish which don't quite make the physical or temperamental cut required to hack it in a main tank.
I keep quite a few cichlids. In order to survive in a cichlid tank you need to be either A) Mean or B) Fast. Now occasionally you'll get a fish, whether it be a cichlid, dither fish, or companion fish that for whatever reason just doesn't make the grade. Other fish will turn on it and attack it relentlessly, giving it the long, slow and harassed sort of death usually reserved for A list celebrities.
If you have a spaz tank on hand, you will have somewhere to keep the fish that are less able to handle the fast pace of the main tank. Nature may be merciless, but that is no reason for you or I to be. My spaz tank has been invaluable in separating out fish and keeping them alive long enough to be rehomed, or to make their home permanently in the spaz tank.
What's in my spaz tank right now? As I type this, there is a Jewel Cichlid I have named “Eeyore” who, in spite of being introduced as part of a pair, quickly found herself the object of all tank aggression. Eeyore prefers to sit on the bottom of the tank and mope about existence, but is otherwise perfectly happy. Also in the spaz tank we have 'spaz,' a pearl danio introduced as one of eight danios designed to act as dither fish. His friends swim happily about the top of the main tank, but little spaz decided that swimming down and banging about the bottom of the tank was a better idea. It would have been an excellent strategy if he wanted to become lunch, so spaz now shares the tank with Eeyore. Another temporary member of the tank is a male betta henceforth unnamed who took ill for no reason, and now looks much better.
Your spaz tank should be at least 20 gallons if you keep large fish like cichlids. If you decide to keep fish which are not aggressive, you may not need a spaz tank, but keep in mind that most boldly colored pretty fish will be aggressive, even if they are deemed “community fish” and the success of your main tank will depend largely on the personalities of the specimens you have.