My fish keep dying

[Yetistroke]

So as a kid I had fish and to be honest all I did was feed them never changed water never cleaned the tank bought all kinds of fresh water fish from Wal-Mart they lasted a few years even added minnows I'd catch in creeks no problems. Now I have a 10 gallon tank same size as I had as a kid and got 2 small koi 4 rosy red minnows a pleco and a peacock eel the ph is at 7.0 nitrate and ammonia is 0.0. After seeing the koi had cotton wool disease I went out bought the bacterial treatment and with in 4 hours of the first treatment of 5 ml (proper amount for 10 gallons per the directions) the pleco died. This is when I tested the water everything was good. I came home this morning two of the minnows died and sill no elevated ammonia and the ph is still at 7 any ideas on where to go. Oh I have a bubble wall thing is it possible that the water is circulating too much with the filter and bubble wall? I'm at a loss and I'm trying to keep these fish for my daughter she thinks it's cool and I can't swap fish out with out her knowing and she gets upset. Any ideas would be great

 

[Aiken Drum]

Welcome to the forum.

How long have you had the tank?

Are you able to give your nitrite parameter as well?

Scaleless fish like plecos are sensitive to some medications. Did you check that the medication you used is good for scaleless fish and plecos in particular? What medication did you use?

Long term i can see all sorts of issues on the horizon. Your tank is simply too small for all those fish. For the koi alone you need probably 50 gallons. Depending on what of type of pleco you had, it could have reached 2 feet in length and needed 150 gallons. Living in unsuitable conditions leads to stress and other health issues.

I would think about getting much bigger tanks or finding fish more suitable for the one you have. Like the minnows.

I would also question 0ppm ammonia and 0ppm nitrate. I dont see how that is possible unless you did a near 100% water change prior to the test. Ammonia is caused by fish waste, which you have a lot. Nitrate is the end product of the nitrogen cycle and under normal circumstances is only removed through water changes. In an uncycled tank you would see ammonia, in a cycled tank nitrate. Are you sure you did the tests correctly? What test are you using?

 

[Yetistroke]

According to the tag at the store the pleco was just listed as a Plecostomus. He was about 1.5 to 2 inches. I used api metafix just checked the bottle I didn't see that it wasn't safe for scaleless fish on it but given the timing I'm pretty sure on that. The koi are going to be placed in a pond once they get to 4 inches or I move out of my apartment in a year. as for the water I did a 100% change cause of sand I put in the tank it was causing constant cloudy water and I read that I creates dead zones in the water in terms of oxygen. For the test I'm using a 5 in 1 test strip that came with the the tank I'm new to the whole testing of the water so I'm not 100% sure I did the test correctly

 

[Aiken Drum]

Please dont think Im disparaging you in any way. Im fully aware you are a newcomer to the hobby and are looking for guidance. We are very forgiving of people trying to do their best for their fish.

There are a variety of plecos, so something labelled as a plecostomus could grow to anything between 3" and 2'. A common plecostomus is the 2' end of things. A lot of fish starts out at the 1.5" size but get huge.

Melofix shouldn't be causing deaths like you describe, its basically a herbal remedy.

Good idea on moving the koi to a pond as they grow. 2 × 4" fish is still too much for a 10g tank given the other fish you have. The eel might need similar consideration regards to tank size as well.

The water parameters are what i would expect after a large water change you say you did, Basically 0. Your test shows what is coming out of the tap rather than what is happening in your tank. Keep monitoring, and let us know if you see anything. Your target should be to keep ammonia + nitrite combined below 0.5ppm through water changes. The assumption, unless you tell us otherwise, is that water parameters before your water change got ahead of this target and that caused your issues. You need to cycle the tank.

Strips are pretty much fool proof, so we can omit user error. But they arent very accurate. A liquid test kit is better.

The cloudiness was probably a bacterial bloom, not your sand. This is bacteria taking advantage of nutrients being out of balance in your newly established tank and should clear up in time.

Link to page containing some useful articles for new fishkeepers.

https://www.aquariumadvice.com/foru...ou-get-started-with-your-aquarium-154837.html

 

[Yetistroke]

Okay thank you I'm going to keep an eye one the water and fish for a few weeks and see if I can get my hands on a larger tank for the meen time