Help needed: one cory died and others are less active

[Fishmomva]

Thank you! I’m going to get an adjustable heater today and bring it up to 72. Thanks for the recommendation on Seriously Fish.

If I switch to sand, how do I do that safely without too much stress on the fish and shrimp and keeping the water stable?

 

[AdoraBelle Dearheart]

Thank you! I’m going to get an adjustable heater today and bring it up to 72. Thanks for the recommendation on Seriously Fish.

If I switch to sand, how do I do that safely without too much stress on the fish and shrimp and keeping the water stable?

Learn How to Replace Aquarium Substrate

Learn how to safely replace the gravel in your freshwater aquarium with this step by step guide, including planning checklists.

www.thesprucepets.com

And a thread here where another member switched from gravel to sand. A bigger job here since it was a much larger and longer established tank: https://www.thesprucepets.com/replacing-aquarium-gravel-1381097

It can cause a mini-cycle, since you're removing the bacteria that were growing on the gravel, so better to keep the tank understocked until you've switched over. A 13 gallon is pretty small for a school of cories too, so maybe consider if you want to upgrade the tank size rather than just switching the substrate. larger tanks are easier to maintain stable water parameters, as well as giving you room for proper schooling numbers. Bronze cories (your corydoras aenus, the normal bronze colour and the albino) can get to a pretty decent size.

 

[Koglin]

@AdoraBelle Dearheart makes a really good point about the substrate. Recently I had a fiasco with a pygmy cory and a fake plant, afterwards I rescaped the tank to be more natural for them - which caused a mini cycle. I dosed prime everyday to neutralize the ammonia and nitrites to help them get my pygmy's through the mini cycle.

For my substrate, after a bunch of reading, I chose pool filter sand with some silica in it, 50 lb bag for $10. There's a number of good options though, this was just the easiest to access in my area that was not all black or all white (all white substrate can be blinding for your bottom lvl fishys, and all black is unnatural for my species of cory). Really wanted something brown or tan like their natural streams.

The sand actually even shows the parameters it affects your water with.

It took longer, but after a super thorough rinsing I also removed a bunch of the silica with a giant cookie sheet (spread it out thinly, and gently rock the pan in a circular motion like panning for gold - the sand and silica will separate to an extent and you can remove the silica). I did this until I had about 10 lbs worth of mostly sand left, then I let it sit in a bucket with w/ old tank water for a day, conditioned that water again halfway through and stirred it thoroughly every few hours.

The pygmy's have been more playful around the tank, seem to be enjoying themselves more and my plants took really well to the filter sand, doing better than ever after adding a root tab.

Hope this helps!