Did I kill these fish?

0 nitrates in a highly planted tank like yours is very common. I can't comment on the fish dying as I've never owned rainbows before.

 

I don't think you having zero nitrates is problematic, as long as it's because the plants are soaking up the extra nitrates.

However you do have stocking issues. What's the temp of your tank?

Temperature tends to be at 77-78 F, I'm aware that I have fish that prefer colder water, theyre leftover from when I was cycling the tank (danio/Cloud Mountain), I'm prioritizing the fish that prefer warmer water

 

Are you going to rehome the cooler water fish then? Not really fair to them, as they'll have a shorter lifespan at the higher temps.

In the future, I wouldn't get fish just to cycle with them, and then rehome them. Not really fair to them. A fishless cycle or a fish-in with fish you plan to keep is better.

 

Are you going to rehome the cooler water fish then? Not really fair to them, as they'll have a shorter lifespan at the higher temps.

In the future, I wouldn't get fish just to cycle with them, and then rehome them. Not really fair to them. A fishless cycle or a fish-in with fish you plan to keep is better.

The place where I purchase all my stuff re-buy fish at 1/3 of the original price, they have many clients that like to go through various sort of fish so I suposed I'd be dropping them there eventually.

 

Sooner rather than later would be best. And then you have room to add more fish.

What's the sex ratio of M to F Boesemani?

 

Sooner rather than later would be best. And then you have room to add more fish.

What's the sex ratio of M to F Boesemani?

I don't know I didn't ask them.

 

Aren't they in your tank? If they're adults, you can sex them:

(see Sexual Dimorphism)

 

Nah theyre all baby and colorless right now!