Help Super Red is Sick! :(

Ok I finally got around to check PH and it's 7.75ph sadly the pale super red didn't make it found him lying between the wood I added motionless this morning. :'(

I'm now worried about his twin, he's looking emaciated, he isn't eating the green beans I've been adding in there for him and the other two plecos...



Here are tank updates added some swordtails, plants, and wood caves:







Here are the betas in isolation: Mean Fish!

Sorry to hear about the loss.
From the pics it seems there is a lot less plants than I initially thought. I'd look at the substrate again. The presence of diatoms (brown algae) on the substrate makes me wonder.

Just a question though. Your having problems with your fish yet you decide to add more? Does this seem like a good idea? And not one or two but like 15? Did you quarantine the new fish first? The filters are going to have to adjust to the increased bio-load, watch your parameters.

Well if you think it's the tank and not the fish I can move him to another tank, none of the other fish are exhibiting any problems, and being that this tank is in the living room it is closely monitored.

The guppies, mollies, swortails are all naturally from areas with higher hardness and even sometimes some salt. They have been bred for generations in the aquarium so are pretty adaptive to tank conditions. Bettas, partially due to their natural conditions, are pretty tough fish as well. The super reds are selectivly bred fish so could be more sensitive to water conditions. Don't know if moving the plec at this point will help much as in a stressed, weakened condition it could be more detrimental then helpful.

I do think its partially the tank. You need to get a handle on what the current water parameters are as I don't think ammonia, nitirite & nitrate readings have been given yet.

Yup ph 7.75 at the top of the post. At highest my plecos will take 7.3 but not much more or they get unhappy.

I have access to 2, 5 gallon carboys which I could fill locally with R/O. Do you think using the 10g of R/O in addition to some tap water at each water change would be enough to lower my PH permanently?

It could be a combination of things including the co2 you are running causing not enough oxygen in the tank especially at night. The rest of the fish are all up high, plecos sit down the bottom and get less air. The photo shows the pleco down in the spongefilter tube? Perhaps he has to sit there to get enough air?

Have you tested for ammonia, nitrites and nitrates?

Using a bit of RO water with the waterchanges may make the ph a little more comfortable for the pleco.