Aggressive BN

[gsveda]

In my planted tank I have three bristlenoses: one large male named Spike, one small golden female named Peach, and one medium sized female named Spot (we thought she was a boy, but apparently not).

I have them cohabitating with emerald eye rasboras, marbled hatchets, siamese algae eaters, peppered corys, kribensis (two males, placid behaviour), and two apple snails (one golden, one pale blue). The tank is divided down the middle by a branch of wood, and the various schools have worked out their territories and tend to get on quite well, even at feeding time.

So far so good, they're all eating well and behaving as expected, however Spike has recently become aggressive and tends to bodyslam my cory cats if they get too close to the burrow he's excavated in the gravel underneath the branch. We thought maybe he has eggs under there but until I can get hold of a little mirror on a stick, I can't see into the burrow to confirm it.

The corys have moved to the other side of the wood where he doesn't hang out so that's ok, but now he's also taken to attacking my apple snails. He zooms out and rams into them until they tip over and retract.

I discovered last week that one of my snails is now missing half of one of her labial feelers (the ones around the mouth part that look like moustache), and the other is missing a huge piece of flesh on his foot. I'm not sure whether the blame lies with Spike though - I haven't seen him biting, just ramming and chasing. I've moved both snails to my quarantine tank to recuperate.

What do you reckon? Is Spike the culprit or am I unfairly pointing the finger at him just because he's the only one exhibiting aggressive behaviour?

Is there anything I can do to break his behaviour? I thought maybe moving stuff around in the tank so he has to start again with the territory stuff, but the branch is too big to reposition. Maybe I should take away his girls?

Poor damaged Blue (healing has begun so it's looking even weirder now):

[Ira]

I doubt it was the BN that did the damage. They can't bite. :lol: They attack more by poking with their cheek spikes.

But it could be he knocked the snails over and some of the other fish took advantage of it to nibble on them.

[SamH]

Yeah, I wouldn't guess the BN had anything to do with it. Mine are so peaceful, except the older ones to each other.

[gsveda]

Thanks guys, I guess that leaves the mystery of how it happened. I'm scared to put him back in there incase he dies next time though - it was looking really bad for him for the first three days and he's only just started to come right.