ANYWAYS i have three surpae tetras aswell as you can see. well surpae tetras do have a tendedncy too fight. they do so to decide ranks. it all naturell. but to make if the fighting starts to get fatel or seriously harmfull i would suggest puting them in a group of five or six.
You are correct in stating that it's to establish ranks, Tetras4me. An alpha male in the group will assert his dominance over the others. He is usually the fish with the most impressive finnage. My alpha is easy to spot and one of my favorite fish.
But why wait until the fighting becomes harmful or fatal?
Serpae tetras can tend toward aggression if their numbers aren't in check. They can also turn on other fish and start nipping. It is really best to address agression issues before they result in a compromise in fish health, which could lead to disease.
I am no expert on synodontis catfish, but Synodontis eupterus gets to be 6 inches long, way to big for a 10g tank. If you could find a bigger home for them, MeanHoney, that would be best.
Tetras4me, I know you mean well, but there are several species on your list where the numbers need to be amended. Tetras are schooling fish and appreciate greater numbers. A nice number to aim for is 5, but the 7 neons you have in your tank is much better. I am assuming that you plan to increase the numbers of your schooling species, which also include the harlequins as well. Rainbows also prefer to be in groups. In addition, and I'm only saying this to help, bala sharks are also schooling fish. Schooling fish that can grow to be 13 inches long! Not the best fish for a 55g tank. Finally, make sure you know what species your pleco is. Several species can reach 2 feet or more in length. But other species only stay at around 5 inches or less. It's great that you want to help out, and I encourage continued research and reading.
55 gallon
7 neon tetras
6 blck neon tetras
1 dimond tetra
4 x-ray tetras
2 bueanos arieas tetras
3 surpae tetras
1 rainbow shark
2 two inch bala shark
1 pleco
2 zebra dainos
3 harlequin rasboras
1 paradise fish
Warmest regards, and I hope that your situation with your Serpae tetras, MeanHoney, improves. They are really a fantastic fish.
llj