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Neon Tetras - Odd Behaviour

11K views 6 replies 4 participants last post by  ChrisR 
#1 ·
Hello, I have 6 Neon Tetras in a community aquarium. They all appear to be fit and healthy, and in the few months since I introduced them to the tank, they've all got along peacefully together, always together in a group.

Today I noticed some odd behaviour. The group now appears to be seperated, 3 of them seem to be keeping a low profile, maybe even hiding. The reason for this is because one of them appears to be attacking any other that comes near it.

Upon closer inspection, I noticed that the one who is doing all the 'attacking' is quite a lot fatter than the others, which led me to wonder if it is pregnant, and that this is some kind of 'defence' or protection thing going on?

I'm not intending to breed any of my fish, but if nature has taken it's course, then I have no clue about signs of pregnancy, or what to look for. They just all look very unsettled at the moment, and I haven't made any recent changes in the tank. Can anybody advise me?
 
#3 ·
Ok I attempted to take some pics, sorry they're not very sharp, I've arrowed the 'fatter' tetra, but I don't know how well you can see it in the pictures. The temperature is normal, about 75 degrees. One of the other tetras is actually hiding in a dark 'cave' in the rocks, and whenever the 'fatter' tetra passes by, it darts out of the cave as if to attack, then darts back in again! Very unusual and unsettled behaviour among all of them!





 
#4 ·
It could just be the fish's personality. From what I know about tetra (and it isn't much), they require pretty specific conditions to spawn, so I doubt it's "pregnant". It may just eat more, or is constipated which leads to bloat. If that's the case, then he doesn't feel good and is acting cranky.

In my shoal of black phantom tetra, I had one fish that hated all the others. None of the other fish showed any aggression at all. I tried quarantining the mean fish, moving things around my tank so he couldn't establish any territory, isolating him in the tank, nothing helped. I finally had to take him to the pet store and trade him for a new tetra because his aggression couldn't be curbed.
 
#5 ·
Thanks for the replies. I thought things were better when I got home from work and switched on the light in the tank. The Neon's were all back together again as a group, and the 'fat' one didn't look so fat anymore. It could have been constipation, but I'm wondering if it was pregnant and and had maybe laid her eggs? I thought perhaps the odd behaviour may have been a 'territorial' thing? Does anyone know if Neons can be like this when in the process of laying eggs? Now that Neon has gone back to chasing all the others around again :(
 
#6 ·
A female carrying eggs would not do the "attacking," it would be the male fish (all of them) chasing her. I suspect this was not related to spawning. Getting neons to spawn is very difficult; they are extremely specific as to water parameters and light (must be dim, nearly total darkness). On the rare chance they did spawn, they would also readily eat the eggs as soon as they were expelled from the female unless the tank was set up to provide suitable spawning habitat.

With almost all characins, females are rounder than males once mature.

A temp of 75F is good for neons; as someone mentioned, cooler that "normal" tropical temperature of 77-78F works better for neons, and 75F is fine. We have fish profiles here, second tab from the left in the blue bar at the top; info on fish requirements can be found in the profile of each species.

Byron.
 
#7 ·
Thanks Byron! Well, everything appears to be back to normal in the community today. All the Neons are grouped together again, and the 'fat' one .... isn't fat anymore! So the mystery is over, maybe it was just cranky as some of the others suggested. I'm glad they all settled down again anyway. Thanks to everyone who replied :)
 
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