Fin Niping

[Salty the Fish]

Hello all,
This is my first post! So be nice?
I've had fish tanks for about 20 years now. Currently have; 1 30 gallon standard tank, 31 gallon tall, 55 gallon box Discus tank, and a 75 gallon tank.

Anyways, to the issue at hand. In my 75 gallon tank I have; 1 red spotted cream severum (4 inches), 2 bala sharks (4 inches each), 2 Iranian red rainbows (2.5 inches each), 3 Goyder river rainbows (2.5 inches each), 1 Uruguay pleco (4.5 inches), 2 breeding pairs of empire gudgeon (2.5 inches each), 1 black ghost knife fish (3 inches), 1 yellow tail eel (5 inches), 2 fire eels (6 inches each), 1 julii corycat (1 inch). I used to have 1 breeding pair of electric blue acaras.

The issue I came acrossed first only was with the bala sharks with their fins being heavily nipped. But this I explained away when I observed them fighting after a feeding. Next, a few days later, my pleco's dorsal fin had 2 large circular nips out of it. I've seen little nips from time to time and had never really been concerned with it but these nips were much larger and deeper. Then a few days later the Severum received multiple massive circular nips on his tail fin and his pectoral fins were shredded. This made me throw out the idea that the fin nipping was the severum. (Usually the fish doing the nipping doesn't have nips, when in a passive tank). So then I turned to the fairly aggressive electric blue acaras. For the the safety of the tank I removed them. After I removed them I observed the tank for 1 month. During that time the nippings became worse. The severum is heavily nipped to the point where his is missing probably 25% of his tail. The balas are even more shredded. And the pleco has recieved more large bites. (Please note that I have taken into consideration the chance of this being caused by an infection but after reviewing documentation of fin killing infections it is very clear that it is fin nipping.) Also something to note, is that no other fish in the tank is receiving any kind of fin nipping damage. So I'm left wondering who is do the nipping to my once pretty severum and to my pleco. (The balas fight so I'm not convinced they are being nipped). Currently I believe the nipping is derived from the balas which saddens me because I had beautiful electric blue acaras but I got rid of them as they were the first suspects. I have never observed this agressive nipping behavior from the balas on other fish. But no other fish has a large enough mouth to make such large nips or the strength to nip through hard fins like the pleco's. (Bala's have a powerful sucking bite that can be heard outside the tank. Sounds like a very hard tongue click). So I'm at a loss as to who it is, and believe the only viable choice would be the bala sharks. The eels are still small and have tiny mouths, the ghost knife is tiny and has a small mouth, but i guess they should be put on the suspect list as well. This doesn't explain why the only targets are the severum and pleco (However the tiny julii corycat has a mean streak a mile long. I wouldn't put it past him to be the culprit but framing the bala sharks, haha).

I'm asking for anyone with applicable fish experience to shed light on the situation and give input. Thank you!

 

[ImACoolguy]

Stocking deficiencies aside, I would say the Bala likely are the culprit. If not given a group of 5 or more(they like to shoal) then I can see aggression becoming a factor.

Aside from that, have you done a water test? Very curious about the nitrate reading of this tank as a few of those fish, namely the BGK, Bala Sharks, and fire eel, will easily outgrow this tank.

I saw an adult BGK in a 75g on YouTube, needless to say it looked quite a bit cramped and it was alone in the tank..


Caleb

 

[Salty the Fish]

Stocking deficiencies aside, I would say the Bala likely are the culprit. If not given a group of 5 or more(they like to shoal) then I can see aggression becoming a factor.

Aside from that, have you done a water test? Very curious about the nitrate reading of this tank as a few of those fish, namely the BGK, Bala Sharks, and fire eel, will easily outgrow this tank.

I saw an adult BGK in a 75g on YouTube, needless to say it looked quite a bit cramped and it was alone in the tank..


Caleb

Hey thanks for the reply! Yes I believed the bala sharks were the issue and was contemplating the addition of more. But was hesitant, because I was not sure if the addition of more would reduce the fin nipping on other fish as it is an establish habit already. All water perimeters are great (ph is slightly low due to the tank being planted and over 4 years old, but this is expected) I've actually never had any tank troubles ever *knock on wood*. The larger fish, BGK, bala sharks and fire eel will take some time to out grow the tank and when they do I know some great aquariums that take the fish I've had in the past. (Of note: 3 foot arowana, now 5 feet in a zoo). So have no fear for the fate of my fish, if you see the sizes I put they are all very small at the moment. (But I do appreciate it!)

So the main concern is, will the establish habit of fin nipping in the current bala sharks continue to the new ones? Or is this, like some cichlids, just a product of not having more same species to fight with?