Injured Glowlight Tetra

Evening All,

I have a 64ltr tank which houses 5 x Glowlight Tetras 5 x neon tetras 1 x Betta 2 x Drawf gourami and 2 x Otocinclus and the tank is about 4 months old and everything has been running smoothly but now I have noticed that my Glowlight tetra is missing his top fin, it looks like it has been bitten off(see pic below). This is a first for me so not sure what cause of action i need to take ? Any advice would be massively apprectiated.

Hi sue,

As always thank you for your wise words.

Do you think the tank is big enough for one more neon and one more Glowlight ?

I agree - provided that the injured glowlight isn't showing signs of suffering (eg becoming inactive, hiding, refusing to eat), then I'd just let him heal naturally through ensuring that water is kept in optimum condition with 0 ammonia and 0 nitrite and nitrates no higher than 20ppm above whatever your tap water level is.

If you rehome the betta into a small tank of his own, which I also agree would be a good idea, then I'd err on the side of one more glowlight and one more neon tetra (rather than two of each). Otocinclus should ideally be kept in groups too - but your tank is relatively young and adding any more at present runs the risk that any additional ones may not have sufficient food as the biofilm doesn't tend to develop until 9+ months. So, at the present time, if you added one more of each of the tetras to bring their respective shoals up to 6, then it gives you the option further down the line (say in 6 months' time) of adding a couple more otocinclus.

Hope that helps.

It could be that. But it could also be something wrong with that fish that we can't see but the other glowlights can. It is common among shoaling fish in the wild for them to kill weaker members of the shoal. Weak fish attract predators because they are easier to catch, and the healthy fish in the shoal don't want predators nearby so they kill the weak fish themselves.

Do you have a fry net that you could use to keep the attacked fish away from the others? This would also give you chance to observe the fish for any other symptoms.

That's the idea. if the other fish can't reach him to pick at him he should heal faster. And as he's in the same tank as the others with their chemical signals in the water, he shouldn't suffer from being alone like he would be in a quarantine tank.