Fish keep dying in two tanks.

[IFLAquatics]

Wait, so only 2 water changes in a month and a half?

What are your test results?
How often are you feeding? And what are you feeding?

Unfortunately yes we have only had the ability to do 2 water changes, (and i think it was actually probably about a month) the levels in the tank were testing perfect before hand but the bottom had crud. The pleco was literally dirtying the tank after a water change in days. We feed a decent pinch of sinking cichlid gold pellets to the eels and algae wafers 2-3 times a week for the pleco. He seems to like the pellets too though. We havent tested since we did the water change and that was stupid. I should have done that before replacing everyone, i have always just taken precautions against NEW tank rather than OLD.

 

[tlindsey]

Sounds like you have anaerobic bacteria in the sand where you have denitrification happening, basically a conversion of organic matter to nitrate and then into nitrogen. When you do a water change, the sand is getting stirred up, and exposing the anaerobic bacteria oxygen. This will disrupt the denitrification process, and release nitrite and/or ammonia into the water column.

This tank isn't planted right?

What type of filtration do you have?

How deep is the sand?

Are you vacuuming to the bottom of the sand?

What type of sand?

And you're not doing weekly water changes? If so how much?

^
This

 

[IFLAquatics]

With that stocking I would be doing a minimum of 50% every week with a good substrate vac. From your reply it sounds like the tank is only getting a 40% every 17 days unless I am reading it wrong.

Not regularly, dont hang me guys, i normally have pristine tanks 24/7. We just went through a big move and money has been tight and we have had alot on our plates. We just had to put down our dog yesterday, he was old and had survived heart worms and years of abuse and his heart just started giving up. Almost 10 years old. Sorry, anyway we take good care of all of our animals and we hate to see them suffer and we have been falling behind and we are trying to figure out how to get that tank back to business. Its still dirty after an entire cleaning (sand is a pain to clean)

 

[IFLAquatics]

No plants, pleco killed the lilies, Its a penguin biowheel, 2 inches of sand, petco substrate sand, yes i am vaccuming to the bottom but i dont get enough suction from my hose to pull up the gunk for some reason, the globs get bad from the pleco. We are starting up a strict regiment on all of our tanks weekly 40% water changes. Our cichlids dont get dirty for some reason, sparse gravel with a small raphael, albino BN pleco 6 various cichlids and a marbled crayfish

 

[Rocksor]

You will have to stock considerably less. Sand is the easy to maintain, even with a gravity powered gravel vacuum. This is how I clean my #22 sized sand. Also, you are considerably under filtered, which I believe will also lead to the problem of losing close to 50% of your beneficial bacteria during a water change as well. You should have a couple of canisters for a tank that size and with so many fish.

So a stinky tank is the a result of lack of weekly water changes, not enough biofiltration, and heavy bio-load. The 2" sand isn't helping as it's keeping more crud underneath.

 

[MrsE88]

Sorry to hear about your dog
Life gets busy and that’s understandable. In the future I’d cut out feeding entirely when you find it hard to dedicate time to the tanks. Even better if you can do a big water change after the finale feeding. This will buy you more time before the tank needs attention.

For now, I’d toss the filters on a different tank with the fish and do a complete clean out on this one. Put any rock, wood or decor in the tank you put the filter on. That way you save as much bio as possible. I’d probably toss the sand and start over. Or remove it into buckets and wash it really, really well before replacing it.

 

[IFLAquatics]

You will have to stock considerably less. Sand is the easy to maintain, even with a gravity powered gravel vacuum. This is how I clean my #22 sized sand. Also, you are considerably under filtered, which I believe will also lead to the problem of losing close to 50% of your beneficial bacteria during a water change as well. You should have a couple of canisters for a tank that size and with so many fish.

There are only 4 fish in the tank.....

 

[IFLAquatics]

For the bichirs, in the 75, 4 fish is too many? And then other question, the only one that survived this was our large bichir, who is just going to get his own tank anyway, so i was just going to cycle the tank with no fish in it and do daily small 3 - 5 gallon spot cleanings over the next week, stirring sand to move debris up from the bottom, then vaccuming it up. I was going to run the tank like that until it is spotless and then reintroduce the bichir, or my juvenile dovii for growing out. Does that sound like it will work? Its just alot of water to be having to break the tank back down again, and im trying to still find a safe but effective solution.

 

[Rocksor]

There are only 4 fish in the tank.....

You said you have eels, 3 bichirs, and a pleco. What did you have before the water change in the 75g? And how big are the fish?

So a stinky tank is the a result of lack of weekly water changes, not enough biofiltration, and heavy bio-load. The 2" sand isn't helping as it's keeping more crud underneath.

 

[IFLAquatics]

You said you have eels, 3 bichirs, and a pleco. What did you have before the water change? And how big are the fish?

So a stinky tank is the a result of lack of weekly water changes, not enough biofiltration, and heavy bio-load. The 2" sand isn't helping as it's keeping more crud underneath.

Sorry i mispoke. I use the word "eel"interchangeably with them because of the pet store name "dinosaur eel". Before the incident, there were as follows
1- 12 inch polypterus senegalus
1- 3 inch polypterus senegalus
1- 3 inch polypterus senegalus
1- 10 inch common albino plecostamus

After the incident, 1 -12 inch senegalus and thats it.