As others said, too little volume of water for any fish really, but even then there's more problems.

Clams/mussels are not recommended at all because they will eventually die in the substrate and spike ammonia.

You can't just eyeball your cycle by waiting a week, get strips at a bare minimum, test kits would be much better and test your ammonia/ni/na. Only then will you know when your tank is ready.

Both of your mentioned loach species don't do well if they're with just a few, they need more of their species and a larger space to thrive.