Cardinal Tetra Schooling Question

Captain Hook

Looking for ideas
Aug 21, 2003
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Sorry to start on another thread on this, I know there are a few...

I'm going to buy about 2 dozen cardinal tetras for my 72. I was thinking of having just them in the tank. But I want them to school and stay in a fairly tight group if possible.

Should I buy a larger fish to make sure they do this? If so, what kinds of fish would work well?
 
Its a catch 22 i think. Any fish large and scary enough to force them into a tight school will probobly actually be able to eat them. Cardinals are just not a very "tight" schooler although they stay pretty close to each other. Fish like Rummynose swim in a much tighter school naturally.
 
I liked a few serpae tetras with cardinals, only 6 serpae to 30 or so cardinals was enough.
 
knashash said:
Its a catch 22 i think. Any fish large and scary enough to force them into a tight school will probobly actually be able to eat them.

Agreed. Also, putting a scary fish to force them into school will keep a hi stress level on your fish, and this would not be fair. (even if they are not going to be eaten.

A bunch of around 30 cardinals will look great in that tank. Put some long leaved plants in the background (the more the merrier) and that will look awesome.

Remember cardinals need a mature completely cycled tank to survive.
 
Mine school in the evening after the first light goes out although I'm not sure why. During the day they are spread throughout the tank but prefer to hang out in the more densely planted areas. The largest fish in the tank is a powder blue gourami which they are used to. In time I'd think they would get used to anything in the tank that doesn't give them any grief so the chances of keeping them constantly schooling is remote, unless it involves stressing them out, as mentioned.
 
True schooling behaviour is very hard to attain in standard aquaria...
The problem is you need a much larger tank in order to provide the needed swimming area for them to exhibit true schooling behaviour. In a tank that size (70+gal), they may try to school but as soon as they get moving as a school the lead fishes reach the end of the tank are are turning around into the rest of what is now a confused mass.

A tank with the area needed would be very large, even for Cardinal Tetras.
A round or spherical tank would be ideal, but implausible.
A good general rule for schooling fish is "The more the better.", when trying to encourage tighter schooling, but once again along with more fish comes the need for a bigger habitat.
 
As to adding a predator to induce tighter schooling...
That would be like turning them into dither/target fish, they would get harassed and/or killed slowly but surely, even in a very large tank with adequate cover.
Cichlid and other predatory fishkeepers often do just this to disperse or release natural aggression/territorial instincts from other displaytankmates.
If your willing to lose fish to the attrition then go for it.
 
I have several schools of smaller fish in a 180g with a few balas, 3 of which are pretty good sized and they still don't school all that much. My scissortails are by far my best schoolers. I still think your tank would look awesome though, so I wouldn't let the idea that they might not school perfectly turn you off from it. Hope to see pics if you go for it!!
 
I just added 30 Cardinals in my 72 yesterday, and they have been extremely active and all over the tank ever since!!

As for bigger fish eating them, if they are full grown they won't or shouldn't. I bought Jumbo cardinals (that were quarintined more then a month) and put them with my pearl Gouramis, Gold Gourami, Some clown loaches, 2 Bushynose plecos, and some other smaller fish.

Nobody is really bother or even thinking of bothering the Neons. One thing i noticed though. The more neons or cardinals you have, the more they will be active. In my other tank i have 15 cardinals, but they rarely ever move, and hide, even though i have no other fish in their except shrimp.
 
Holly9937 said:
I have several schools of smaller fish in a 180g with a few balas, 3 of which are pretty good sized and they still don't school all that much. My scissortails are by far my best schoolers. I still think your tank would look awesome though, so I wouldn't let the idea that they might not school perfectly turn you off from it. Hope to see pics if you go for it!!


I have a 180g and looking for schooling fishes too. Scissortails are great, but I am a little worried that since they grow to 4" I can't keep too many of them. Besides my water is really hard, not sure if scissortails can handle that.
 
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