Normal neon tetra behavior?

[Ac30fan]

Neons looked happy for several days after coming home from store. Swimming together in open water, at all levels of the tank, and interacting well with Rasboras.

Last few days, they have been grouped together in the lower left rear of my tank. Since yesterday, I've lost 3.

Rep at LFS said its not uncommon to lose a few tetras after purchase. So what's up with this behavior?

Water params are good: 0 ammonia & nitrites. Nitrates are somewhere under 20

What's going on?

 

[Canary bird]

Neons looked happy for several days after coming home from store. Swimming together in open water, at all levels of the tank, and interacting well with Rasboras.

Last few days, they have been grouped together in the lower left rear of my tank. Since yesterday, I've lost 3.

Rep at LFS said its not uncommon to lose a few tetras after purchase. So what's up with this behavior?

Water params are good: 0 ammonia & nitrites. Nitrates are somewhere under 20

What's going on?

I have some black neon tetras and they do this, but I've had them for well over a year , they come out to feed then slink to the back of the tank and hide behind the plants , occasionally one or two will stay out the front it's a bit like a look out ... "Let us know when she's gone " lol .. They seem to prefer it when the light is out, so I've started setting my lights to come on at 2pm and off at 9pm ...ill see if this makes them anymore adventurous

 

[Fishfur]

Neons can be inbred, as are many fish today. You may have some unfortunate specimens. It is not odd to lose a few, sometimes you lose most of them.

Stores sometimes get shipments that are poorly handled, or handle them poorly themselves. Sometimes the fish are too weak to tolerate the change to the home aquarium after the change from home to shipping to store tanks.

It's a lot of stress for any fish, I'm sometimes surprised more of them don't die, they are not handled all that gently. If they are not wild caught, they may have been sick before they even left the farm, and all the stress on top of it is too much for many of them.

Only thing you can do is try to buy fish that have been in the store tanks for at least a week, preferably much longer, and are eating well. Keep your tank as clean as possible and don't overfeed.

It's sad to lose them but it does happen, unfortunately.

Edit. Fish are like any other animal in that if they feel unwell, they try to hide it as long as they can. Looking different or behaving differently in nature makes you a target for predators, so it's a survival instinct to hide illness until they can't do it any more. Dogs and cats do the same thing. So they may have looked ok at first, until they felt worse.