Here is what my
betta suddenly started looking like about a week ago:
From the side:

From the top:
Its not easy to see in the pictures, or even in person, but there is a certain transparency to the bubble, it looks clear inside. And I just noticed this, he seems almost dirty in spots, there is something light brown on him (fungus?), on his sides and his caudal fin and head. It can be seen in the pictures, although it looks a bit darker brown than in person.
Needless to say, I'm exceedingly worried.
I'm in such a state that I can't even tell if there is any pine-cone scales viewed from the top, and would really appreciate an objective opinion on that.
His home, parameters, and diet:
He lives in a 10 gallon aquarium which he has completely to himself, he's been there since I got him last July. It is filtered and heated.
ammonia is 0, Nitrites are 0, Nitrates are always below 20
PPM,
pH is 6.6 and very stable, temperature is 79 degrees.
I change 1/3 of the water every week. I treat the water with Prime.
Normally (before I got lazy recently) he had a staple diet of Hikari Betta Bio-Gold Pellets, he got 4-5 a day. Twice a week he got the freeze dried medley (daphnia, mysis shrimp, and bloodworm mix) as a treat instead of the pellets. However, lately I've been lazy and have been feeding mostly the freeze dried medley.
His behavior:
He's a bit less active than usual, but since he's always been exceedingly active he's still within what would be considered normal for most fish - but not for this spazzy guy. He isn't swimming lopsided, and he isn't scratching against anything.
Recent changes to his aquarium:
I've made several changes to his tank within the last month - I put in live plants, some Dwarf Sagittaria, Anubias, and Java Fern (and for them to survive I've also put laterite in with the bottom of the substrate, got new gravel to cover that, and have been putting Nutrafin plant glo and got a new brighter light for him) and I also have started putting in some black water extract. All of these changes date back to three weeks ago, and I only noticed his stomach about 1 week ago - and its the kind of thing I probably would have noticed right away. It didn't happen gradually, either - suddenly, there was a ginormous bubble in place of where his stomach was!
What I've tried so far:
He's been fasting for 3 days, and the 3 days before that he only got 3 pellets instead of 4-5. He hasn't recieved anything freeze dried since this happened. I've tried getting him to eat some thawed, shelled, and mashed peas but he is having none of it.
Do you think it is dropsy or constipation? What about this light brown stuff - is it fungus? What treatments should I be trying - if it at home things I'd appreciate step-by-step directions. Please help me help my Betta!
Edited to add: I tried cooking the frozen pea, then shelling it and cutting it to itty bitty pieces instead of mashing it, and he ate it up. However, now that I've found the little light brown things on him I doubt it is simply constipation...it looks an awful lot like fungus.
Also, if this is something contagious what precautions do I take to keep it from passing to my other tanks? I have a 5 gallon with another Betta and a 75 gallon with Dwarf Neon Rainbows, Panda Cories, Otos, Harlequin Rasboras and Gold Tetras. All of the fish in these tanks appear and act very healthy.