? Help!! Please!

[Spiceyseal]

Ok first off my english is not so good so i apologize. I may be in the wrong area for this problem for that i also apologize and would appreciate any redirection needed. I have purched 3 pleco from the local fish store and all have died within a few hours. I am not sure what kind of pleco they are seeing as how i cant take a pic of one i will just describe it. It was mostly black with some grey. Had a sucker mouth. Here in ny it is the most common to buy at a fish store.
Tank temp 70°f
Ph normal
55 gal tank
Normal tank gravel
Fluval 55 gal. Filter
Feeding tetramin tropical flakes
I have 3 tiger barbs
3 died tetras
2 mickey mouse guppies
One kuhli loach
One grey cory
I discovered some small "mites" in the tank and i wonder if they could be the cause. They are about the size of a head of a pin. And appear to be clear with dark spots. They seam to resemble a common flea found hear in ny. Anybody know what they are called? If they are dangerous for plecos? All other fish seam just fine. I have added other fish at the same time as the pleco and all others live. Only the pleco are dying. Thanks for reading!

[Mol_PMB]

Welcome to the forum, and I'm sorry to hear about your problems with plecos.

Common and bristlenose plecos (it's probably one of those types) are usually pretty tough. Please don't buy any more until the problem is diagnosed. If they're dying so quickly in your tank but not in the shop, I suspect that it may be something to do with a big mismatch in water parameters (possibly toxins in the tank, or maybe a big difference in temperature, hardness, nitrates etc). Not many diseases or even normal toxins act so quickly.

Without knowing more information it's difficult to help. Do you have a water test kit and what are the results?
How long has the tank been set up and what is your maintenance regime?
How did you acclimate the fish?

[Spiceyseal]

I have a ph tester but no other type. Ph came back mid range. The tank has been up for about a month. We did one 30% water change and a gravel syphon. I left the fish in the pet store back for about 20 mins to a half hour. We were worried about lack of oxygen. After a few hours all of a sudden he started flipping out. He swam erraticaly almost panicky acting. The other died after a few hours as well. That one seemed to not be able to latch onto the glass. He tried and would slip off.

[Mol_PMB]

Ok, I'm going to guess here.
If the tank has only been set up a month and already has quite a lot of fish in it, then probably the nitrogen cycle in the filter is not yet fully established and you may have high levels of toxins in the tank (ammonia and nitrite are the important ones).

I would suggest your next purchase should be a liquid test kit (I use the API Master Kit which measures ammonia, nitrite, nitrate and pH) which will be more accurate than the test strips and last longer. Here it costs about £20.

Without the results for ammonia, nitrite and nitrate it's really hard for us to help.

[Spiceyseal]

So no one has any idea about bugs? Or mites? I took a sample of my water to petco and they tested it all came back really good. I am not buying anymore untill i get it figured out. I purchased 2 Chinese algie eaters so hopefully they will halp

[stuby]

You need a heater in the tank.... raise the temp to ~78 degrees. The other fish in the tank may be able to handle the room temp tank but the pleco will not.
When you got the plecos home what did you do.... how did you put them in the tank???? The "bugs" could be a lot of things..... I am assuming they are harmless because your other fish are fine??

Chuck