Lemon aggression.

marshallsea

I had to change from hard water to soft GH-7, KH-5, PH-7.3. I wanted to get rid of the Platys (4 adults in a 20g with a lot of fast growing plants). Lemon Tetras looked like a good replacement so I ordered 12 Lemons. When the LFS called I collected and gave the Platys to the LFS as I got the Lemons. The next day I got a small ammonia increase so I did a 50% wc. Day 3 I have ammonia-0, nitrites -0 nitrates 10-15ppm. Today the Lemons became active and some doing their little dance. One in particular started herding the rest into a corner, chasing the ones who tried to escape. I thought this was normal due to them establishing a pecking order but I saw one in the back with his tail nipped 1/2 off. Within 30 mins. the tail was all gone. Is this normal for a new group in a new (to them) tank? Will the tailless one regrow his tail or is that his end?

Byron

Re the tail, if the fin itself is nipped off but some is still present at the base, the fin will usually re-grow. But if the nipping extends onto the caudal peduncle, likely not; and in this case, other issues may occur too, like fungus, bacteria, etc, so keep a close eye on them.

I've not personally maintained this species, but they are said to be quite peaceful. So this only shows that not all fish within a species will adhere to the norm for the species. Of course, there may have been any number of factors causing severe stress to bring this about, long before they reached your tank.

Byron.

marshallsea

Yes, you never can tell. It's strange, I had set the tank up with a lot of floating plants to provide dark areas for their comfort ,while the herding and fin nipping were going on they were in the darkest corner. I saw the torn fin so I moved the floating plants to the side and removed all shaded areas, instantly the herding stopped and they began to school like I've seen in You Tube videos. Today I've left the floating plants on the edge and will give them shade in few days and see if they've settled down.