Im at a lost please help!

[a123andpoof]

So I have my fish blinky and for a while I have been having problems. He is almost 3 and could easily be 4. I dont know how old he was when I got him, but he is going on his 3rd year with me. He is in a 10g tank he shares with blurp a fiesty female. My problem.

Housing
What size is your tank? 10g
What temperature is your tank? 75
Does your tank have a filter?yes
Does your tank have an air stone or other type of aeration? no
Food
What type of food do you feed your betta fish? top fin
How often do you feed your betta fish? 2 times a day
Maintenance
How often do you perform a water change? 1x per week
What percentage of the water do you change when you perform a water change? 25% to 50%
What type of additives do you add to the water when you perform a water change? Prime

Water Parameters:
Have you tested your water? If so, what are the following parameters?

Ammonia: 0ppm
Nitrite:
Nitrate:
pH:
Hardness:
Alkalinity:

Symptoms and Treatment
How has your betta fish's appearance changed? He is really skinny. He is a large fish, and his head is huge in comparison to his body.
How has your betta fish's behavior changed? He doesnt eat much if anything, he just lays around doesnt have any energy. Blurp got on his side, took a small chunk out of his tail. He hid in the corner while she dominated the tank. he was never aggressive, but believe me in his prime he could have taken her.
When did you start noticing the symptoms? a few months ago, but it just keeps getting worse.
Have you started treating your fish? If so, how? I dont know how to treat him
Does your fish have any history of being ill? no
How old is your fish (approximately)? 3 to4 years

I am thinking he may be just getting old, I just hate seeing him this way. Is there really anything I can do, or am I just going to have to wait it out?

[twissfish]

Have you tried removing the female? She could be stressing him out. That's all I can think of that could be the problem at the moment.

Does he have any symptoms of another illness? Sores? Fungus?

[a123andpoof]

I have been having the problem before the female even went in. At first I thought it was the smallness of his first tank a 2.5 so I upgraded to the 10g and it didnt help any.

And no there are no other signs of another illness.

[shellieca]

+1 with twissfish. I wouldn't put a male & female together unless their breeding. I would remove one of them so he can destress & heal up.

[a123andpoof]

Trust me it isnt the female. He was like this before she even went into the tank. I am thinking if anything he needs something smaller.

[twissfish]

I highly recommend you remove one of them just in case and see how he goes from there. There have been very few times where I've seen someone successfully place a male and a female together.

[Mo]

Hello...

I would remove the female aswell. They could be getting stressed from being in eachothers sight or knowing th presence of the other due to smell in the water. He could have been having issues before but the stress of the female could be elevating the level of stress therefor making the issue worse. A stressed Betta is a Etta that is more susceptible to diseases such as fin rot and fungal diseases

[shellieca]

All I'm saying is that the female is not helping & is probably causing him more stress which doesn't help his health. Neither of them need something smaller, but that's me. I would not have the two of them together especially knowing ahead of time he is lethargic & hardly eats. Have you tried crushing the pellets? Have you tried feeding frozen blood worms or brine shrimp? Based on the amount of time you've had him, it's possible his condition is due to old age, but I've not had experience with it so someone who has will hopefully chime in.

[a123andpoof]

Alright. I will go and get a heater today and take him out. I think he needs something smaller just cause he seems to have a hard time moving around. He eats bloodworms so I feed him those like every other day. And sometimes I can get him to eat one pellet. But its not enough to get weight onto him. This morning he just layed there not coming up for food or anything which is why i am going to down size him again. I think the 10g is just to big.

[Mo]

A Betta at an old age who is weak should ideally just be placed in a smaller 2.5-5 gallon tank with many hiding areas... And broad leaved plants fake or live is okay just aviod sharp decorations or plastic... You want broad leaved plants near the surface so he doesn't have to struggle as much to reach the surface and take a breath of air. Keep water conditions pristine and cause him minimal stress. The sight of a female or female in the same tank can cause stress to some bettas... Old ones seem to be more drastically effecte by it IMO/E... Good luck. At this point just remove him from the tank into a smaller tank with a bunch of broad leaved plants near the surface...l keep the water warm and try not to stress him out that much....keep his diet nutritional so he can stay strong. Give him frozen treats x2 weekly. And feed a very good pellet or flake food. New Life Spectrum is a good pellet you can find at Petco. Hope I helped