I got two bolt catfish at 3"-4" from Ted's Fishroom the Summer of 2015 ($90 each), which makes them now about 2 years old. Now they are about a foot already. I fail to discern any external differences between the two. Very lively assertive catfish, easy to feed, not vicious with tank mates, graceful yet robust with beautiful markings, but they have zero tolerance for each other. It became evident from the start. Ted shipped them to me separately, of course, but I combined them for acclimation. When I returned in a few minutes after I had just let them out of their bags into an acclimation cooler, I found the bigger one had already dug into the smaller one. Yikes.
Luckily they heal well. So they grew up to about 6"-7" in separate 240 gal tanks in about 6 months. Then I combined them in one of our 4500 gal. They haven't fought too badly at first but then it gradually changed. They do keep away from each other but every time they bump into each other, it turns into a cartoonish ball of two bending and flying bodies (if there was dust, they'd be in a cloud of dust) where each simultaneously tries to bite the other and avoid being bitten by the other or pull a fin out of the other's mouth... Time has not helped it. Their fins are usually ripped and barbels are half bitten off, as you will see in the video below. Lately I started noticing that the dominant one has started giving an occasional chase to our much larger 16"-22" vulture catfish.
I am thinking I will need to separate them again next time I pump down the tank. Here is a short video compilation. The dominant one occupies the coveted bottom section right in the middle of the strongest current. The indomitable challenger scours the walls all around the tank and the viewing window:
Luckily they heal well. So they grew up to about 6"-7" in separate 240 gal tanks in about 6 months. Then I combined them in one of our 4500 gal. They haven't fought too badly at first but then it gradually changed. They do keep away from each other but every time they bump into each other, it turns into a cartoonish ball of two bending and flying bodies (if there was dust, they'd be in a cloud of dust) where each simultaneously tries to bite the other and avoid being bitten by the other or pull a fin out of the other's mouth... Time has not helped it. Their fins are usually ripped and barbels are half bitten off, as you will see in the video below. Lately I started noticing that the dominant one has started giving an occasional chase to our much larger 16"-22" vulture catfish.
I am thinking I will need to separate them again next time I pump down the tank. Here is a short video compilation. The dominant one occupies the coveted bottom section right in the middle of the strongest current. The indomitable challenger scours the walls all around the tank and the viewing window: