By looking at them its hard to tell. But I will take a stab at it and say they are both males. The top one is a yellow lab the bottom one looks like a red zebra. Your yellow lab looks like he has been getting beat up. I would add some hiding spots for him if he is being harassed. Another thing to consider is getting a bigger tank if you plan to add more fish, how big are the fish now? As for him not eating you could try some brine shrimp or pellets soaked in garlic juice. I have 4 yellows and I couldn't get them to eat for anything and then realized I had a bully in the tank that would not let them eat. I would keep an eye out for harrasment. Another thing we will need to know is your water parameters