I have 4 African Dwarf Frogs in a 10 gallon tank with a betta. The betta is super nice and has never attacked anything in the tank, but as time goes on, the frogs are getting to be absolute jerks. They've been in the tank a bit over a month now, and it all started a few days ago. Now that they understand where food is and come out within a few minutes of me dropping food in to scavenge the bottom, they have also started to bicker with each other every day at food time. They will pile on top of each other and start biting each other's feet to see if they're edible. Then today, one of them latched on to the other one's belly and wouldn't let go for a solid 30 seconds or so while they both scrambled and kicked at each other. He eventually let go, but they seem to be getting more aggressive with time. Is this sort of behavior normal from these guys, or is there something wrong with them?