Total change in behaviour

[stg1969]

Hi All.

For 3 months or so I have been building/cycling/stocking my Fluval 180 tank.

I followed all the right procedures and eventually ended up with the following stock.

6 x Tiger Barbs
6 x Gold Tiger Barbs
8 x Rummy Nose Tetras
2 x Yoyo Loach
1 x Bristlenose Plec.

Now, the Tiger Barbs I expected to be aggressive at times, I have had them before.

However, they were complete wusses, even getting picked on by the smallest of the yoyo loaches (who was about 2cm. The Gold Tigers that I got from a different store seemed more dominant. Even the largest of the Tiger Barbs who is bigger than everything else in the tank, used to hide in my plants and keep a low profile.

Fairly recently however, I had some disease and ended up losing 4 of my Tigers. Leaving only the smallest one, and the largest one.

Since then, the large Tiger has decided to "grow a pair" and is now chasing everything in site and being a complete bully. I can't see the logic in this at all.

I know people say keep Barbs in schools to minimise aggression, but I figured this was aggression towards eachother. How would losing 4 of his own kind suddenly make him brave.

One answer would be I guess that one of the 4 Tigers i lost could have been dominating him, but from what I remember, all 6 of the Tigers were complete softies.

Anyone have any theories on this behaviour, and is it possible that buying 4 more Tigers may resolve it, or just make it worse.

The only thing the large Tiger doesn't pick on is my Plec, who is as chilled as a stoner.

Thanks in advance for any advice.

 

[Colin_T]

The fish is acting aggressively because it is stressed out.

Barbs naturally occur in large groups and panic and stress out when not in large groups of their own kind. The fish is no longer in a group and the stress from this is causing the fish to become aggressive.

 

[stg1969]

The fish is acting aggressively because it is stressed out.

Barbs naturally occur in large groups and panic and stress out when not in large groups of their own kind. The fish is no longer in a group and the stress from this is causing the fish to become aggressive.

Thanks,

So if I buy 4 more barbs this should potentially resolve it?

 

[Colin_T]

yes it should help

 

[Byron]

Thanks,

So if I buy 4 more barbs this should potentially resolve it?

Not necessarily, and I'm afraid less likely tyo succeed than not. Once a shoaling species fish has become "dominant" it is not usually going to change. This is because the original group was probably keeping the hierarchy in check, but once four of the six died the dominance came to the forefront. The Albino Tiger Barbs should have helped, as this is the same species just an albino variant, but this is not guaranteed.

Tiger Barbs, whether original, albino or green varieties separate or combined, should be in a group of at least 10; you had 12 which was initially good. But even so, squabbling may still occur as not all fish adhere to the general rules for the species. There is also a danger for the other species in the aquarium.

Your two Yo Yo loaches are also a problem waiting to happen. Botid loaches are highly social fish, and need at least five of the species. I don't know how long you have had the two, but adding three more now again might or might not work. But the stress on these two is something to recognize. The tank size (dimensions especially) also factors in to this.