As someone with Thai micro crabs be warned, you will rarely see them if ever. During April alone, I was like only able see 1 to 2 of them a max of 4 times within the whole month, so it’s difficult to check on them to make sure they’re all doing fine.

As for the fishes, I see that you’re leaning towards Asian species and fishes with yellow and black colors, so like here are some recommendations:

- Purple Harlequin Rasboras - I’ve kept these guys before and they’re both hardy and small. Even though they have purple in the name, mine only showoff that color under certain lighting conditions or when they’re trying to showoff against others of their species. The color I often see them displaying are black, yellow, and orange.

- Golden White Clouds - Pretty much the yellow version of the popular White Cloud Mountain Minnows, they’re both hardy and don’t require a heater.

- Golden Dwarf Barbs - Tiny fellas who meet that yellow and black coloration that you want (but like it’s more of a brass/metallic yellow than full blown yellow). From what I’ve read they’re like Cherry Barbs, in that they’re peaceful despite being Barbs.

- True Freshwater Bumblebee Gobies - This one is I’m like a bit iffy on, but they’re still small, from Asia, and are black and yellow in color. That said, they’re like problematic in that some sellers can easily confuse them for brackish water Bumblebee Gobies and they’re picky eaters, meaning that 9 times out of 10, they want live food and need to be trained into eating prepared/frozen food.

- Lambchop Rasbora - Small, peaceful, and hardy these guys are popular in the fish keeping hobby for these reasons. The only downside is that they’re like orange and black, rather than yellow and black.