Trouble in Paradise

[xspainx69]

Well I started my 75 Gallon tank about a month or so ago. Its fully cycled and I have the following fish.

I have :

2- Figure 8 Puffers, 2- Molly's (Male & Female), 1- Mono Sebae, 1- Archer

I have them at 1.007 SG


Heres my problem, I went and I bought a small 2 inch Columbian Shark Catfish and a Mono Argentus. So I brought them home and after drip acclimating them I put them in my tank. The Figure Puffers from the begining started pecking at the Catfish, they would continiously pester him. According to the research I did on Mono's, they love to be in schools and they dont like to be alone. Now I put in a Mono Argentus and the Mono Sebae chases him all over the tank and pecks at him...

So now I am looking at all this mayham unravel and Im like What In God's Name Is Going On Here!!!!!!!!

The next morning, I find the Columbian Shark Catfish dead and half of his body is left and the Puffers have a bulging stomach. The Mono is still alive, 2 days later I come home from work and the Mono Argentus is dead.........Now I am thinking it was the puffers, but then im like wait a minute, the Puffers never went after the Sebae, so why would they go after the Argentus, they look like identically the same.... So the mysterious death of the Argentus is weird Im not sure if it was the Sebae that killled him since he didnt like him from the get go, or whether it was a puffer ambush at night time.

My question now is, what do I do....Im afraid to buy new fish..... I am not sure how the Little Demons (Puffers) will react when they see a new fish. I wanted to get a Knight Goby and maybe an Orange Chromide, but I dont know how the "Tank Inhabitants" will react

I want to get a Columbian Shark Catfish again, but should I get a BIGGER one? Maybe the puffers wont mess with it , if they see its bigger than them? I dont know what do you guy think? I dont want to get rid of the puffers, but I may have to find them new homes if they will limit my ability to add new members to the tank.

Also setting up another tank just for them is out of the question.

[Pufferpunk]

LOL, guess you can't pick your puffer's friends... No really--sorry for the deaths in your tank.

I have a fahaka puffer who is very nice to let many fish live in the same tank with him. Some are potentially "delicate" species, like 2 18 year-old elephantnoses & black ghost knife. He has lived with several of these fish for many years. My stepdaughter wanted to give me her large parrot cichlid & the only tank I had room for it was the fahaka's tank. Within 6 hours, Filbert killed it. You just never know with puffers...

[xspainx69]

Any ideas??? Do you think that If I get a bigger Columbian Shark Catfish, they'll leave it alone? Any tricks for puffers? Does anything change their mind set? Like taking them out of the tank and rearranging the tank and then puttting them back in?

Should I bother getting a Knight Goby? Or is that just making another expensive meal for the Puffers? I also wanna get a Scat, but Im not sure how they will react to it?

[Nick]

A Columbian shark will get WAY too big and eat the puffers, possibly killing itself in the process. Scats are schooling and are much more aggressive in pairs or less, to each other and tankmates. The store where I work often gets them in as pairs, and the more aggressive often harasses(sometimes to death) the less aggressive, then starts on other fish. They also get a solid food long. Both species like a slightly higher brackish than the F8's. I'd stick to archers and knight gobies, much better size and SG matches.