'happy' School Fish

[ziggyboy]

Hi all, newb here. Sorry if this is a silly question but I can't find an answer anywhere. I have seen posts and sites claiming school fish are 'happiest' with at least 6. I don't know about you but that sounds a bit cryptic to me. What exactly is happy? How will it affect the fish...and will it die if I only get 2? Thanks!

 

[dwarfgourami]

It depends on the species. Glass catfish do actually quite often pine away and die if they find themselves without a reassuring crowd.

With danios and other fish where hierarchy is important you are likely to see aggression problems, as the dominant fish works non-stop at establishing its top position and the same poor inferior fish gets beaten up again and again until he finally dies from stress.

Other fish may simply become very timid and/or skittish if they do not feel safety in numbers. If you keep a single khuulie loach, you are not likely to see very much of it: keep a school of 10 and they'll quite likely dance all over the tank. With fish whose natural behaviour involves constant interacting in a large group- well, you're not going to see much natural behaviour if you keep them on their own or with a single mate. And seeing natural behaviour is for most of us the great thing about fishkeeping. As far as we can judge at all, interacting does seem to be something that gives pleasure to such fish as corydoras.

Some fish will only spawn in groups, another indicator that they need the group to feel safe.

 

[loachman]

it usually means that the fish is healthy and displaying its natural behavior.

 

[arif_93]

it menas they eat swim and live healthy
they dont fight with each other and are peaceful
they dont chase anything around

 

[three-fingers]

and will it die if I only get 2? Thanks!

Basically. It's not just as simple as getting 6 of them, it depends on many factors.
If you only get two of them, depending on the species they will become aggressive and nip all your other fish, become inactive and boring - sometimes sulking in a corner...slowly wasting away or become very skittish.

Happy fish are generally active, not scared of movement (like when you walk up to the tank and open the lid to feed) and 100% healthy.

The thing is, the fish people recommend you keep in groups are usually the ones that live in massive schools in the wild - numbering in the hundreds or thousands. It's a safety in numbers thing.
When you keep too few of them, they feel insecure and this can have the aforementioned effects on them...it's basically like depression.
6 is just a good number really, 5 wont make too much of a difference, but it depends on the tank. If you only had 6 neon tetras in a 100 gallon tank with large fish or no other fish at all, they will suffer those effects.

But in a - say 20gallon tank - that has been set up for years with similarly sized fish of a peaceful temperament, the odd tetra may do OK on it's own. This is usually the case when you start of with a large shoal and over the years they pass away leaving you with 1 or 2. By this time the fish will (or should) be 100% comfortable with their surroundings, and the other fish around them can simulate the safety in numbers thing.

 

[blcknwitecuban]

like fingers said it is a safty in numbers thing but if a fish feels safe in the tank then they'll probably start 2 move away from the group. most people say silver dollars should b in a shoal but i have one and hes fine and doesnt run and hide if i go 2 the front of the tank or anything becasue it feels safe but im sure he would b happier if i got him a buddy or 2

 

[Tokis-Phoenix]

I agree with three-fingers, a lot depends on the exact type of fish you have, what other fish you are keeping it with and how many gallons the tank is and its dimensions. In a 10gallon tank for example, 5-6 neon tetra's would be fine, but in a 100gallon tank there is so much more space and such a small minimum sized shoal of neons would feel very insecure and probably quite stressed, so i would advise having at least 10 neons etc.
No shoaling fish is exactly the same as the next, a lot about achieving a happy shoal of fish depends a great deal on the exact types of fish and tank set up you have . The minimum of 6 shoaling fish thing is just a basic guideline/rule of thumb and mostly applies to peaceful shoaling fish in small or average sized tanks with peaceful small to medium size fish stocking.