Uuuuuggggh! My 20L just crashed. Now what…..

[Ken Burke]

I think my ammonia spiked pretty hard, and I lost most if not all my plecos (it was a grow out tank). 
 

I’m thinking do a huge water change, make sure all the dead fish are out of the tank, and wait a month or so be for add fish back.  Thoughts?

 

Edited October 10, 2021 by Ken Burke

[lefty o]

my first question is did you test for an ammonia spike, or how did you come to that conclusion? next up would be if it is in fact an ammonia issue, what caused the spike, and how long has this tank been up and running?

[Ken Burke]

On 10/10/2021 at 9:38 AM, lefty o said:

my first question is did you test for an ammonia spike, or how did you come to that conclusion? next up would be if it is in fact an ammonia issue, what caused the spike, and how long has this tank been up and running?

My nitrites were higher than expected.  Could have been chlorine following water chang, but a pleco got stuck in an in tank filter and died. 
 

I don’t trust my api kit.  Well I could be the problem, but either way my results are all over the place

Oh, and the tank is about 1 year old

 

[lefty o]

so pleco died i assume unnoticed at first. that could for sure throw things a bit out of whack. id do a few water changes, then test every few days for a week or two, and see what is really happening. the tank could be good to go in a week, or it may take 3 or 4 weeks. let the tests, and whatever else is alive in the tank be your guide.

[Ken Burke]

On 10/10/2021 at 1:07 PM, lefty o said:

so pleco died i assume unnoticed at first. that could for sure throw things a bit out of whack. id do a few water changes, then test every few days for a week or two, and see what is really happening. the tank could be good to go in a week, or it may take 3 or 4 weeks. let the tests, and whatever else is alive in the tank be your guide.

Good advice, there are still a few plecos, shrimp and endler in there.  I added a little salt, figure it’s like chicken soup….can’t hurt.

[lefty o]

a little salt is never a bad thing.

[Odd Duck]

Something to keep in mind (not knowing anything about how large the first fish that passed), if a single fish dying caused a big enough ammonia spike to cause more deaths, your biofiltration was probably overloaded and running on the ragged edge of handling the bioload in the tank.  A single fry passing in a grow out tank shouldn’t cause a tank to completely crash.  Typically, your biofiltration will grow with the fry if it was previously decreased from a low bioload status.  It’s unusual to have a full on crash from a single fry death unless you’re exceeding your filtration by quite a bit.

Maybe consider adding more filtration, or flow, or whatever you need to do to make sure you don’t have another big crash?  Just a thought.

[gardenman]

Crashes happen. When they do the best thing is to correct the immediate issue, in this case remove the dead body/bodies, change enough water to get things back to a "normal" level (or use an ammonia neutralizer if a water change is impossible) and then put everyone still alive back in to keep feeding the bacteria. Your bacteria didn't die unless you did something stupid, and if it was handling the bioload before the crash it should handle the bioload after the crash. There will be even less bioload as the dead fish is no longer contributing to the bioload. If you're going with a bare bottom tank you might want to consider adding gravel as it'll give bacteria more places to live. Bacteria likes to colonize things and if you have fewer things you have fewer places for the bacteria to colonize. More surface area gives you more places for bacteria to live. Gravel can vastly increase the amount of surface area in a tank for bacteria to colonize. A second filter (sponge or fluidized bed type) can help immensely also. You want lots of housing available for bacteria.

[Torrey]

My fry tanks have floating plants, and I increase the plants as the fry grow, to offset my bare bottom (my fry tanks are the only bare bottom tanks I have). More plants = more roots to absorb ammonia and more area for beneficial bacteria to colonize.

[Dwayne Brown]

I would add some fast growing substrate and floating plants to your aquarium. Species such as Pogostemon stellatus, water lettuce, and duckweed. Suck up a lot of the nutrients in the water and it will help you keep the nitrates down.