Welcome to our community
Okay, you have a couple of Tiger & one red Oscar. The red Oscar has got one hell of a deformed mouth, has it always been like that? Also, keep an eye on its head, it looks like a little bit of HITH but I can't be sure, maybe it had it and it has already healed.
Now, your tank looks very nice, you've done a really good job. Now we would be neglecting our duty if we didn't point out that keeping these fish long time in a 75 gallon tank is not a good idea. Obviously I don't want to put a damper on things just when you join, but we need to point out these things.
By the way, I can't see your plants lasting very long