PlanetCatfish.com

I borrowed a friends digital camera and managed to get a good close up shot of my Pictus. To me he doesn't look like a Pim Blochii. But I'm no expert. The top of his tail fin also curls over. I haven't noticed that trait in Pim Blochii..

The only reason I'm wondering is that the Pim is becoming increasingly aggressive. Which from what I have read about Pim Blochii they are fairly peaceful, except with small fish. The Pim is sharing a tank with an Oscar and has taken to chewing on him during the night. Which startles the Oscar and sends him into a panic smashing into everything in the tank. And I woke up the other morning to a battered and bloody oscar with some seriously torn fins. Luckily he's healing well, no signs of fungus ect..

I would not have believed it was the Pim's doing but I saw it with my own eyes. He's been pretty peaceful up until with point. It was just a sudden turn. The Pim will also take a 'stab' at me during cleaning, feeding ect.. He never did that before.

Any idea as to what species of Pim he is? Maybe it will explain his aggression level.

His eyes look cloudy in the pics for some reason.. I think it was the flash since I had to leave the tank light off in order for me to get a close up shot of him without him running for cover. He's also a little beat up since the Oscar took some revenge yesterday when the Pim bit his tail fin. The oscar got a few bites in before I could get over there.

Ignore my lovely gravel.. it's going when I upgrade.. LOL

Yup, that is a member of the P. blochii species group. The whole group is a mess consisting of more than one species, which explains the differences in behavior reported.
FWIW, I have two P. blochii that are reasonably peaceful and look almost like your fish (except for being a little more blotched in the dark areas)...they have the upper lobe of the caudal fin curling over as in your fish.
How big is it anyway?

Oh ok.. I was thinking Pim Blochii was a single fish, not neccesarily a group. So I assumed he was something else. Thanks for the info.

Currently I'd say it's about 5 inches without tail. I've had it since it was tiny. So the attitude change was a shocker to say the least.

Would adding more cover for the Pictus maybe slow the aggression at all? I just need to settle him down a bit until I can upgrade tanks and see it that helps.

It doesn't hurt to add more cover. My bigger blochii is about the size of yours and I've had no aggression problems, even after I added a second, smaller blochii in the same tank much later.

Silurus, is P. blochii a shoaling fish? I bought a group of four, and haven't had aggression problems apart from them harmlessly chasing each other around. I wonder if the Pim is frustrated by lack of this interaction in the pecking order, and taking it out on the Oscar.

No, I don't think they are shoaling. The two I have stay apart from each other, and there is very little interaction between them. The bigger one used to be alone, but I didn't see it bothering the other fish. Even the false jaguar cat (Liosomadoras morrowi) in the same tank was nastier to tankmates than the pim.

I re-arranged the tank and that helped for one night but he's back at the torment again tonight. I just shut off the tank light and the Pim darted out of his hideout and went straight for the oscar. I'm going to try adding more plants and hopfully that will help. If it doesn't I'll have to figure something out.

The damage he inflicts to the oscar is really not that bad. Just torn fins basically. The problem is the oscar freaks out and damages himself. I've been leaving the room light on and that's helping somewhat so the oscar can see when the Pim is coming. But every morning there are still new injuries. To both fish now. The oscar must be battling back during the night. The way it's starting to look now is that they will have to be separated. And I don't have another tank big enough to hold either one of them. It's either they live together or one will have to be re-homed. Which is the last thing I want to do.

I'm also thinking the problem is the Oscar is smaller than the Pim. Not by much. The oscar is about 4 inches without tail. But the oscar was introduced as a 1 inch baby and there was no aggression then.

Ahh... these fish are driving me insane. LOL

this is fascinating to me. i have owned my pimelodus blochii for about 8yrs now and in all that time he has never shown any agression. he is now about 12" at last measurement and shares a 6x2x2 tank with other south american catfishes and cichlids.

actually he once did take a dislike to a pseudoplatystoma fasciatum in a smaller (4x2x2) holding tank. he chased it into a corner and left it there. hehe i did remove him before the p. fasciatum got any size on him. at this stage the blochii was 10" and the fasciatum was about 6".

Ok thanks.. So it probably is related to size. Since the Oscar is smaller than the Pim. Could also be that the Pim is maturing... He's getting about that size.

Do you have any pics of your Pim? I've never seen one at adult size.

One option is to put a clear plastic divider in the tank to keep the two separate. You can buy one at the LFS, or failing that, make one yourself.