Danios showings cuts and dying

[DevoPast]

Hi there

Over the last 3 days, I've lost 3 of my zebra danios and have a 4th looking like he might go soon. The first two I found dead on the filter intake, but the 3rd was floating with two vertical cuts, bleeding from both. I currently have a 4th with a single vertical cut, bleeding a little, and swimming with labour.

All of my water levels are good, ammonia 0, nitrites 0, nitrates >5ppm. PH is around 8, water is a bit hard but that's normal in my region. All other fish are in great shape. Ideas of what might be going on?

 

[Mumma.of.two]

What other fish are in the tank?

 

[Bobbym9]

Do you have a water circulator where the fish can swim into the propellor? That is what happened to one of my zebra danios.

 

[fishman1121]

Did you observe any bullying maybe?

 

[DevoPast]

I haven't observed any bullying, and I just lost #4 and 5. 4 had a cut but #5 didn't... My other fish are serpae tetras, neon tetras, java loaches, CAE, rubber lip pleco, a few Rosie red minnows and some scissor tail rasboras.

All other other fish are in good condition. Not sure what's happening to the danios. They're gold and pink danios if that makes any difference to you.

 

[DevoPast]

It looks like I'm losing another one. This one isn't cut though. He looks a little bloated, and is just drifting around near the surface. Doesn't really respond to any stimulus. I waved the net near him and he barely reacted. Looks like the other one who died last night. Could this just have been a bad batch of danios?

 

[Mumma.of.two]

Are they new fish? I would be keeping a close eye on the serpae tetras and CAE. CAE in particular can get really nasty and start picking on tank mates.

 

[DevoPast]

They were newish fish. Had been in the tank for about 2 weeks or so. The remaining fish look fine. Might have been a bad batch.

The CAE seems ignorant to everyone in the tank other than our pleco haha. He chases the pleco when it gets too close. But the CAE usually just buddies up with the java loaches and minds his own business. I keep him well fed with cucumber and shrimp pellets. Getting real big quick though lol.