I've recently added 4 new fish to the tank in the last 2 days...
1 x Albino Shark
1 x Rainbow Shark
2 x Aussie Tandanus Catfish
I'm pointing the finger at the tandans because they are always in the salmontailed's sleeping log. But what of the sharks? Could they be responsible? The Sharks and Tandans are roughly 2 inches long. They are in a 3 foot tank (though it could be 2 and half, but I think its 3)
I've seen the rainbow shark constantly chasing the poor albino one around the tank, but yeah... anyone got any ideas?

PS: The only other tankmates are a few tiny brine shrimp and feeder guppies and a small 3cm bristlenose pleco.