Betta not acting right

[Jadet18]

Housing
What size is your tank? 6 gal
What temperature is your tank? 77-79
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? 6 endler livebearer males, 2 otos, 2 zebra nerite snails

Food
What type of food do you feed your betta fish? pellets
How often do you feed your betta fish? 2-3 morning, 2 night

Maintenance
How often do you perform a water change? once a week
What percentage of the water do you change when you perform a water change? 25%
What type of additives do you add to the water when you perform a water change? I make up the water before hand - it's RO water, with added minerals, then PH buffer to get it to be 6.6-6.8

Water Parameters:
Have you tested your water? If so, what are the following parameters?
Tested on Sunday, but not since

Ammonia: 0
Nitrite: 0
Nitrate: 5-10
pH: 6.5
Hardness: ?
Alkalinity: ?

Symptoms and Treatment
How has your betta fish's appearance changed? Not really
How has your betta fish's behavior changed? Yes - acting more lethargic, not as active, not eating as much, "breathing" hard and hanging out near top of tank or resting on one of the plants
When did you start noticing the symptoms? A couple days
Have you started treating your fish? If so, how? no
Does your fish have any history of being ill? unknown - I've had him about 2 months
How old is your fish (approximately)? unknown, at least 3 months - 1 year

I noticed the last few days that my betta, Zorro, has been acting a bit off.

1. Usually he's a pig, but the last few days he has stopped after 1 or 2 pellets and goes to the back of the tank.

2. He's not as active, either, and is preferring to hang out on his hammock, behind the filter, or on one of the plants. Only flaring briefly at his reflection, then "retreats"

3. His coloration looks ok, and I haven't noticed any strange bloating or spots on his body. He is swimming a bit funny though... tail drooping down, so his head is close to the air.

None of the other fish are sick, and all eating normally. Water levels are normal. I noticed there was a bit of cloudiness last night, so did a mid-week water change yesterday of my normal 25%. Water was clear this morning.

The only thing that I can come up with that's different is that I added a new plant (red tiger lily) and moved some plants around about 2 weeks ago. Then I've been trying to figure out the best fertilization routine to make sure everything is healthy.

I do .25ml of multi-nutrient, carbon and potassium every Wed and Sun. I try to do 2 drops of iron (for the tiger lily) every other day, though on Saturday or Sunday I accidentally added too much. Haven't added any since then.

Plants are the tiger lily, hygro difformis, ludwiga, sunset hygro, frogbit, a crypt, and something big, green and leafy I can't remember the name of to save my life.

I have noticed that the frogbit has been dying off in giant groups the last few days as well, which is not normal. They're turning brown and slimy. I've been removing the dead leaves as soon as I see them. Everything else seems ok.

Would the new plant/new fertilizer routine have stressed Zorro out? Or is there something else I'm missing??

Please help! :(

[shellieca]

Well, IMO your tank is overstocked & is possibly part of the reason your betta is not currently well. 6g is pretty small for multiple fish, not necessarily because toxin build but because of lack of space for them to move around & escape each other. In my research, Otos are supposed to be in no less than a 10g. Are you using a liquid test kit? Out of curiosity, what is wrong with your tap that you need to use RO water? I fertilize once a week or two using Fourish & Excel, in my bigger tanks I've added root tabs.

[Jadet18]

I know it's a bit overstocked in theory, but I haven't had a problem with any of the levels since I established it over 6months ago.

I don't think (hope) it's not stress because of space, as the otos kind of hang out with each other at the bottom, the endlers zoom around the middle to lower area, and Zorro has the whole top part to himself.

I use RO water because 1) my water in Arizona is absolute trash, 2) the LFS I get all my fish from uses the RO water and I just figured it was easier to use water they were used to. No real reason other than that

Yes, using API liquid testing kit.

I used to fertilize once a week, but I read that it was better to split up the dosage (so half Wed, half Sun) so the plants get a constant stream of ferts. Is that not right?

[Demysta]

Hmmm... could be a number of things. He could be stressed out from his tankmates, might need a higher volume or water changed, etc. It might be stress more than anything, and I know keeping a proper cycle is tough in anything less than a 10 gallon.
I would highly suggest upgrading to a 10 gallon, putting the other tank mates into it and letting it re-cycle. Keep the betta isolated in the 6 gallon until the water has completed its cycle, and see if that helps him. All I can really say is that its probably stress from lack of space for him. He might feel he's being encroached upon and threatened by the other tankmates in that sized tank.

[callistra]

Your tank is hugely overstocked.. sorry :( You need to upgrade to a 20g or rehome your otos and guppies.

Also those guppys are tail nippers.. I wouldn't put them with a betta. They need a 20g. The otos and snails would probably okay in the 10g.

What are you using to test ammonia and nitrite? A drops kit or strips?

How exactly do you mix up your RO water and exactly what chems are you adding? That ph is too low in my experience to be properly buffered and remineralized.. What is the gh and kh?

[shellieca]

Originally Posted by Jadet18

I know it's a bit overstocked in theory, but I haven't had a problem with any of the levels since I established it over 6months ago. - Its not about the toxins if you have the proper filtration & do proper water changes which apparently you do, its about stress on the fish & housing fish correctly so that they grow properly into adults. Keeping fish in a tank too small for their adult size can stunt their growth which is not a good thing because their bodies may stay smaller but their organs can continue to grow which will kill them much sooner than they should die.

I don't think (hope) it's not stress because of space, as the otos kind of hang out with each other at the bottom, the endlers zoom around the middle to lower area, and Zorro has the whole top part to himself. - I think your Betta is stressed even though the fish all seem to have their own area of the tank. My Bettas are ALL OVER the tanks they are in, top, bottom, middle, sides - EVERYWHERE - I have a 46g, 3 10g, 1 5.5g & a 2.5g & my Bettas use every square inch of their homes.

I use RO water because 1) my water in Arizona is absolute trash, 2) the LFS I get all my fish from uses the RO water and I just figured it was easier to use water they were used to. No real reason other than that - What do you mean by trash? It tastes bad to humans or there are high levels of ammonia, nitrItes or nitrAtes or some other harmful substance that a quality water conditioner & good filtration won't take care of? I think if you didn't have to go to the trouble of trying to adjust the RO water to meet the needs of the fish you might also lessen the stress on them & it would save you money & time possibly. But that's just my opinion.

Yes, using API liquid testing kit. - Good, you're readings should be accurate if the tests are done correctly.

I used to fertilize once a week, but I read that it was better to split up the dosage (so half Wed, half Sun) so the plants get a constant stream of ferts. Is that not right? - I've not read that so I don't know. I know my plants are doing well with the way I'm doing it; I have to be careful when dosing Excel because it causes algae problems if I add too much so I don't dose every week on my smaller tanks.

....

[Otterfun]

sorry, I think your tank is overstock, at least based on a visual on the livestock you mentioned above.

You can run the analysis with this Bioload calculator so you have an idea and check on compatiability on the livestock, etc.
http://www.aqadvisor.com/AqAdvisor.php