Marco from ax has some problems

[Marcopolo]

I have 3 tiger barbs a red tailed shark a clown knife fish a Cory cat fish a plecostimus and a loach that looks like an eel (not sure of technical name), anyways they're in a 38gallon tank and the barbs have black spots and what looks like fun rot. The plecostimus and red tailed shark look like they have it too. I have 2 large plants in the tank. What should I do I just did a water change 15 out of the 38 gallons.

[Hholly]

Do you have a water test kit? What are your ammonia, nitrite, and nitrate readings?

[Marcopolo]

I have an ammonia kit no nitrate one though.

[absolutangel04]

Welcome to the site!
Your tank has some stocking problems, but you can fix that. Thet test kits are very important since nitrate levels and nitrite levels need be monitered too. I recommend getting the API master kit for freshwater. Its a little high, but cheaper than replacing fish. The best thing to do in the meantime would be to change the water. I would actually recommend doing a %50 water change.
How did you pick the fish that are in there? You picked some really cool species, but some of them would be better off in a bigger tank.
Do you have any pictures?

[Hholly]

Nitrites and nitrates are pretty important too. So what is your ammonia reading? I'm a newbie myself, but I believe fin rot comes from poor water quality. You have several fish that produce a lot of poo, in a tank that is probably too small for them. So you need to do more water changes to accommodate that and get them healthy. I'm sure some more experienced people will chime in. But in the meantime, you should study the threads on cycling a tank, and unhealthy fish, to get some more ideas on what you need to do for your own.
Good luck and welcome to the forum!

[redsea]

Welcome to AA!

[Marcopolo]

I just switched out 15 gallons of the 38 yesterday I have my barbs and the red tailed shark in another tank with medicine running through and no carbon filter. When I chose the clown knife I was told he'd only grow to 8 inches and now he's 10in. And I just found out he'll get bigger. What do you recommend for my stock of fish?

[Hholly]

Sound like you need to either rehome some or get a bigger tank.

[absolutangel04]

IMO, the shark, pleco, and knife should all be re-homed. Assuming the pleco is common, he can reach 2 feet. If you wanted to keep all your current stock, I personally would recommend at least a 125g tank. But, you could rehome a few fish and get some smaller guys will do much better in a 38g tank. The tiger barbs would probably like a few more friends anyway so they have a full school.
Is your loach a kuhli, black kuhli, or dojo loach? Those are the eel-like ones I know of off the top of my head.