Looking for American eel for my 125g

[CamsCustom]

Hey guys new here. I'm custom building a 125g tank from scratch and when I'm done I want to add an American eel to hang out in the caves I built please help TYIA

 

[Just Toby]

You will need tight fitting cover glass to stop an eel escaping (and to reduce condensation and evaporation depending on where you are)

I assume the caves are made of something that will not leach lime in to the water? What is it?

Well done on making a tank though.

In the corner you have a pipe with holes in, most of the way down, which I assume is the return from a sump, when the power goes out how will you stop the tank draining down in to (and out of) the sump? Or is it for an external canister filter only (assume it might be or heater would be in the sump?)

 

[CamsCustom]

I plan on making a solid wood canopy cover with plexiglass and a seal (almost like a fridge) and the corner you see was the intake for a sump system but since then I have drilled holes through the overflow (I've decided on a dual canister system and creating an Asian type root system tree to cover the corner with blended in holes to allow water flow into all levels of the tree. And as for the concrete I'm using hydraulic water-stop cement by quikrete ( I tend to follow Joey the diy king on YouTube, and trust most of the products he uses)

 

[CamsCustom]

Also added note I do know I will have to change the water tons of times from the concrete skyrocketing the ph level

 

[Just Toby]

I think you will need to seal the concrete somehow as I think it will leach for too long. Pond construction sealant might do it.