Something is wrong with my albino

Hi.
Im fairly new to keeping fish. i have an albino cat fish living with some tetras, a blue ram and a guarami. ive had them for about 6 months.

ive noticed abit of algea growing lately and it appears my cat fish has stopped eating. his abdomin has changed and looks abit fat. his anus looks swollen, and he has not pooped for a while.

could someone please take a look at these pics and let me know if he is sick? i took the shots at different angles. (the green spot is on the glass)
https://imgur.com/a/4f41F

thanks in advance

It looks like Bloat, possibly caused by to much protein in his/her diet, what were you feeding before you noticed this?

If it's bloat caused by constipation then you could try feeding a few de-shelled cooked peas, peas have a laxative effect on BN's. There is the possibility that the Bloat could be caused by a bacterial infection in the gut or a worm infestation. Try feeding the peas for now and hopefully one of are experts will be able to give more advice.

There is a post about Bloat HERE that may help you.

thanks mate.

i feed the fish flakes, and the catfish just eats the algae growing in the tank. he does an excellent job of keeping it clean.
is bloat contagious? should i be worried about other fish?

YYes, bloat is contagous, but generally only to other bristlenose and other bottom dwelling fish who will eat the bristlenose's poo.

expecting the bristlenose to only eat the algae in the tank is a common misconception, and dont worry, you are not the first and def wont be the last to make it they need a lot of algae to keep going, best the throw in a bit of cucumber every now and again for it to much on and dial back on the flake food for a few days so that the bristlenose can have a chance to recover.

good luck