Fresh water tank crash

[Wingin It]

Originally Posted by dsaundry

I think you may have answered your own question when you said the fish looked like they were gasping for air, they probably were, years ago I had a similar crash and lost 22 Koi angelfish, all my water parameters were perfect, fish were all plump and happy the night before, sometimes when you go and service the tank when you refill after stirring everything up, it depletes the oxygen and they litterally suffocate. I had been doing fw tanks for years and never had a problem, until that happened. Took a while to figure it out as well.

+1 If you don't already have an airstone or bubble bar in the tank i'd definately put one in.

[asylumdown]

So you think it's likely an oxygen thing? The tank hasn't had any major changes in it for about 7 months so it was just so shocking to have this happen now. Other than an airstone is there anything that can be done to prevent it from happening again? Every so often I try and take out most of the plants so I can properly clean the gravel, is this something I need to worry about every time I do that (I know way more about salt water systems I'm afraid)?

[cale262]

I don't vac the substrate in any of my planted tanks,...that's why I have plants,..But if the filter was down for any amount of time the BB could be toast, I always keep a bottle of seachem stabilty on hand for just such occations.

[dsaundry]

Air stone is probably best and agree with fellow member, maybe less vacuuming as planted tanks require less...

[Wingin It]

certain gasses can become trapped under the sand (i'm assuming you have sand) and if it's not dispelled regularly and then suddenly released it consumes the oxygen and the fish suffocate. By adding an airstone you guarantee oxygen for the fish...the only other thing you can do is add an annoying HOB filter that tricles into the tank and creates oxygen that way.

I personally never vaccum my sandbed...the plants are so numerous and the trumpet snails are everywhere so I don't do anything for it. Just the normal water changes and even those are few and far between because it is a heavily planted tank.

[ElGuappo]

I use an aquaclear filter because it agitates the water and adds oxygen.
Now i also added a koralia incase the aquaclear stops. In the past
in heavilly planted tanks I used an air stone but only at night. I don't
care for the bubbles that much. I just ran the air pump oposite
to the lights.

[othicx]

like Wingin It said, i can almost say for sure that it was the vacuuming of the gravel that released ammonia and what not into the water which starved the fish of air. I personally do water changes 2 times a month. and have a bubble stone in the tank to keep the water airated.