Betta at the bottom of the tank

[Alcemistnv]

Housing
What size is your tank? 10 gallon
What temperature is your tank? 82 Degrees
Does your tank have a filter? Yes
Does your tank have an air stone or other type of aeration? no
Is your tank heated? yes
What tank mates does your betta fish live with? Three more bettas and an oto cat

Food
What type of food do you feed your betta fish? I believe it's Tetra mini Betta pellets
How often do you feed your betta fish? 3 pieces every day

Maintenance
How often do you perform a water change? Every one to two weeks
What percentage of the water do you change when you perform a water change? 75%
What type of additives do you add to the water when you perform a water change? Water Conditioner And/or Stress Coat

Water Parameters:
Have you tested your water? If so, what are the following parameters? Not as of yet, have been very preoccupied. Ammona was at .25 last I checked only 3 days ago. The tank IS cycled.

Ammonia:
Nitrite:
Nitrate:
pH:
Hardness:
Alkalinity:

Symptoms and Treatment
How has your betta fish's appearance changed? He was bloated a few dasys ago despite not eating, which led me to belive it was internal parasites.
How has your betta fish's behavior changed? He's been laying at the bottom of the tank regularly. Sometimes I find him hiding behind the filter. When he does swim away, he's clamped up.
When did you start noticing the symptoms? 3-4 days ago
Have you started treating your fish? If so, how? Not yet since I don't know what it is and also because I didn't have the time or space to QT him YET. Will be done the day after tomorrow or tomorrow if I finsihed what I need to do.
Does your fish have any history of being ill? He often has days where he's clamped up and energyless. Never found out what was up with him.
How old is your fish (approximately)? I've had him for 4 months and he was full grown when I got him.

[callistra]

If you are showing ammonia and zero nitrates your tank is not cycled. Your cycle may have broken down, but it's going to need a lot of attention for a while. You need to be testing daily for ammonia nitrite and nitrates at this point and making a water change whenever you see as much as .25ppm ammonia. Eventually this will go away and you will see nitrites. Monitor and make changes as needed with this and eventually they will go to zero and you will see some nitrates. This is when your tank is actually fully established. Keep them under 20ppm by doing WEEKLY water changes of 25-50%. If you skip a week you could have problems, especially with that high of a stock. This cycle guide may be helpful: http://www.bettafish.com/showthread.php?t=47838

Also, what filter are you using and are you using a siphon to vacuum the gravel along with the changes?

Usually internal infections where water quality is in question (your ammonia is high enough to cause problems) come in the form of bacterial internal infections,not parasite. If it was parasite he'd probably be begging for food, zig zagging, maybe even flashing on things. In this case I would use epsom salts and fast him a couple days. The epsoms need to be predissolved and pure - check ingredients label that there are no additives. Different people use different dosages. I suggest starting him at 1/4-1/2 tsp and increasing him up to a full tsp after an hour or so. Leave him in the epsoms at least a week. If the bloat clears and his poop is normal color then he was just constipated. If the bloat does not clear and/or his poop is clear, white, stringy or segmented he's got an internal infection. I would bank on it being bacterial and get some Kanaplex. If any at any time you see actually pine coning (scales sticking out) antibiotics ASAP are needed.