Nippy rummynose

[Gypsum]

Today, I caught a rummynose tetras hassling the longfin bristlenose pleco and nipping at its fins. The pleco is usually out and about but is now hiding to avoid hassle. We've had the rummynoses for a while and the bristlenose for about a month, and up until this morning, the rummys have been peaceful, no trouble to anyone. Why would their behaviour suddenly change?

Water parameters are the same as when I last checked, but I introduced some black corys yesterday, who are active and zipping around the tank. That's the only variable that's changed. Could that be stressing out the rummys? I have six and was going to increase their shoal anyway. Is that likely to reduce the aggression?

 

[Byron]

Rummynose tetras are considered a fairly peaceful species, but being a shoaling species the more there are in the group the better. And this species is one that always seems to fare better with 10+ so I would definitely increase the group. I don't know the tank size, nor the fish stock, but if you can manage 12-15 I would consider that minimum, up to 20+.

 

[Gypsum]

It's a 240L Fluval Roma, currently with ten corys, five black phantom tetras, eight harlequin rasboras, six rummynoses, one Bolivian ram, one bristlenose plec, and one raphael catfish.

 

[Byron]

It's a 240L Fluval Roma, currently with ten corys, five black phantom tetras, eight harlequin rasboras, six rummynoses, one Bolivian ram, one bristlenose plec, and one raphael catfish.

I looked up the dimensions and this tank is 47 inches (120 cm) in length, so definitely I would have 20+ rummynose. I had a group of 23 in my same-length tank and it certainly does make them happier.

I would also increase the Black Phantom, this is another of the peaceful tetras where more is always advantageous. I would go for 10-12 in total minimum. It is easy to tell male/female (the red adipose and ventral fins of the female) and a group roughly 50/50 in gender will reward you with some lovely interactions.

You could increase the cories, up to you. In this sized tank I would have 20-25; I had 50 in my tank of this size but it was intended as a home for my cories which I have had for years now.

The raphael I would remove...I'm going from memory but we may have discussed this elsewhere, but never mind, just noticing it and it would be best overall.

 

[Gypsum]

The raphael was traumatising our otos, but they're now in a different tank. No one else seems bothered by it. Why would you remove it? I'd much prefer not to, to be honest. I like it, and the poor thing has already moved around a lot. I inherited it from some guy who was moving to Canada. Indeed, one of the reasons from changing from a 125L to a 240L was to be sure it had enough space, as the 125 was pretty borderline (although that's what its previous owner kept it in).

 

[Byron]

The raphael was traumatising our otos, but they're now in a different tank. No one else seems bothered by it. Why would you remove it? I'd much prefer not to, to be honest. I like it, and the poor thing has already moved around a lot. I inherited it from some guy who was moving to Canada.

Given its size (6 inches, up to 8 inches) and propensity to eat small fish it can fit in its mouth especially at night, and having had one many years ago...but having said all that, it is not all that much of a problem so enjoy it.

 

[Gypsum]

Aye, I know it can eat small things. This is why I never got neons! What was difficult about yours?

 

[Byron]

Aye, I know it can eat small things. This is why I never got neons! What was difficult about yours?

It was as long time ago, back in the 1980's, but if memory serves me, its activity at night seemed disruptive, and it did start to get large...a 6+ inch fish even in a 4-foot tank as mine was is a big fish, and when it is one of the loricariids (actually this species is in the family Doradidae but they are similar) it often is not really a good fit. At 6 inches this fish can easily eat full grown rummynose.

 

[Gypsum]

Mine is 4" and around four years old.

The phantoms are four males and one female. Probably should have more females.

To go back to the original question, should increasing the tetra schools sort out the fin nipping behaviour (although everyone is getting along at this moment)?

 

[Byron]

Mine is 4" and around four years old.

The phantoms are four males and one female. Probably should have more females.

To go back to the original question, should increasing the tetra schools sort out the fin nipping behaviour (although everyone is getting along at this moment)?

Yes, increasing the group should, because the fish "expects" this and studies have shown that insufficient numbers can affect fish and one result is aggression.