Bloated Juvie Blood Red Parrot

Tank size: 125 gallons
pH: 7.6
ammonia: 0
nitrite: 0
nitrate: 5.0
tank temp: 78

Fish Symptoms:
I have a young (5 month?) blood red parrot that has recently, within the last few weeks, become increasingly bloated. Comparing him to the other parrot of the same age, his belly definitely sticks out. He is still very energetic and interested in food. I feed them Omega One cichlid pellets every other day (sometimes less), and bloodworms they find that the black knife doesn't. I've attached pictures, although I don't feel they do justice to his belly. (I know my tank is covered in algae, though not sure why. The bristlenose is taking care of it, though.)

UPDATE: I just boiled 5 frozen peas, chopped them to bits, and fed them to my fish. He ate several of the chunks, hoping this will do the trick.

Volume and Frequency of water changes: 10-15% once weekly

Tank inhabitants: 3 blood red parrots (2 juvies, 1 adult), 1 juvie green severum, 1 adult black ghost knifefish, 1 juvie albino bristlenose pleco, 1 pair adult kribensis

Do you over feed the bloodworms as they can cause bloating.

I would research your fish diet needs as it could do with improving.
Some fish need frozen foods in there diet,veg, wood, etc.

Are the scales sticking out.
Does the anus look inflamed or enlarged.
What does it look like when your fish go to the toilet.

I try not to overfeed the bloodworms, but my black knife always seems like he's starving. I try to feed him a few times a week. I used to also feed him ghost shrimp, but they're impossible to find anymore.

The scales don't seem to be sticking out. The anus does not look to be inflamed to me. I haven't seen him poo yet (although he may have when I didn't see him).

Today when I gave him peas, I noticed he spit most of them back out, but did eat some of the bits. I think I'm going to add peas to their diet regularly about once a week to prevent this from happening in the future. He doesn't seem to be any less bloated today. Should I try epsom salt in a hospital tank?

It's quite common for fish to turn there noses up at the peas when first introduced.
Keep trying.
Also remove uneaten peas from the tank.