Drew04

My rainbow shark was introduced to my 5 bloodfin tetras, 2 rosy barbs, 1 chinese algae eater several weeks ago. The shark immediately established a territory and there were no chasing issues after about 2 days. They all maintained a very peaceful environment.

2 weeks ago, we added a spotted headstander and a koi angelfish. The shark is almost constantly harassing the headstander, chasing it around the tank. The headstander is not aggressive at all and I have never seen it instigate the attacks. It just kinda hovers there, looking at the gravel....until the RS gets angry at him then he just tries to hide.

The headstander is bigger than the RS, so maybe it's a case of napoleon syndrome in the fish word, IDK.

The RS was fine with all the other inhabitants until now.

Any thoughts?

TFA101

i understand similar body appearances set off aggression, particularily in sharks like your rainbow. i just searched up the two and they look nothing alike, not even in body shape. could one be invading the others territory? the next time you clean the tank, try rearranging decorations as best as you can to eliminate any established territories so everyone can establish new homes together.

Drew04

Headstander was found dead last evening. The rainbow shark stayed in hiding inside the hollow of driftwood all evening and night, almost like he felt guilty and didn't want to face us or something.