Who Gives A Fish Forums

I've been noticing my Bangaii Cardinalfish hasn't been coming to the front of the tank as much lately. It's a timid little thing, and still a juvenile, so I'm not too surprised. But today I saw it hiding in the bottom corner, and its tail fin has been nipped. It's just recovered from fin rot, which I think it had when I got it, but its fins have been doing well.

I also saw my slightly larger Clarkii Clownfish, which is still small and tan, charge at the Cardinalfish and nip its fin. The weird thing is, neither of my Clownfish seems to have a fixed territory, and they don't really interact much, except sometimes the female shows the male who's boss, but it's not aggressive.

I've also noticed the female Clownfish likes to sit on a covered ledge, mostly at night, and it has a spot where it likes to dig. I've seen it rub against a big shell near that area a few times, and it's got sand on it from digging. Both Clownfish have black patches on their bodies and tails, which I guess is them growing up, but it's not happening fast. They both let my cleaner shrimp clean them, and they're not aggressive to any invertebrates or my Bicolour Blenny.

So, what's going on here? And what should I do?

UPDATE: Since I wrote this, I've had to separate the Bangaii Cardinalfish, but I'm thinking maybe isolating the female Clownfish could reduce the territorial aggression?

Hi Scott, thanks for your interest in helping me out with my Bangaii Cardinalfish issue.

To be honest, I'm not sure how much info you'll need to figure out what's going on, but I'll give you as much detail as I can.

My tank's a 120 liter, it's been running for about 8 months now. As for rock, I've got a decent amount in there, roughly about 20-25 kg, I'd say.

All my fish have been in the tank for varying lengths of time, my Clarkii Clownfish for around 6 months, my Bangaii Cardinalfish for about 4 months, and my Bicolour Blenny for roughly 3 months.

It's a reef tank, with a mix of live rock and some artificial decorations to provide hiding spots for my fish. I've also got a cleaner shrimp and a few other invertebrates in there.

Let me know if you need any more info, and thanks again for trying to help me out.

talonix wrote: ↑Fri Feb 07, 2025 4:20 pm Hi Scott, thanks for your interest in helping me out with my Bangaii Cardinalfish issue.

To be honest, I'm not sure how much info you'll need to figure out what's going on, but I'll give you as much detail as I can.

My tank's a 120 liter, it's been running for about 8 months now. As for rock, I've got a decent amount in there, roughly about 20-25 kg, I'd say.

All my fish have been in the tank for varying lengths of time, my Clarkii Clownfish for around 6 months, my Bangaii Cardinalfish for about 4 months, and my Bicolour Blenny for roughly 3 months.

It's a reef tank, with a mix of live rock and some artificial decorations to provide hiding spots for my fish. I've also got a cleaner shrimp and a few other invertebrates in there.

Let me know if you need any more info, and thanks again for trying to help me out.

1 - My tank's 180 liters.
2 - There's 27kg of rock in there.
3 - The Clownfish have been in for 2 months, the Bangaii Cardinalfish for 1 1/2 months, and the Blenny's been in for over a month.
4 - Not a reef tank yet, no corals.
5 - The tank's been running since the end of March, so almost 4 months now.

I've been thinking, what if you use a net, bucket and hose, fill the bucket high enough to put the clowns in, just the clowns. Rearrange the rock work, make sure there's plenty of holes, dens, space. This should take around 30-60 minutes to do, long enough to add the clowns back into the system. It'll be like a whole new environment, should work a treat.