What is the name of this sucker fish?

I introduced fishes to my planted aquarium yesterday. I waited one week after planting some carpet and other plants to introduce fishes into it.
I bought 4 neon tetras, 2 gourami, 2 flat white tetras, 2 orange tetra, 4 moulii and two algae eaters. These algae eaters were 3 and 4 cm in length and looked different than the normal Bristlenose Plecostomus.
I found one of the algae eater dead this morning and found it in the bottom of the tank. Can you please let me know whats the name of this fish and its characteristics?.

Hillstream loach, they are friendly

It’s a hilstream loach and they require different parameters and tank conditions then all your other fish and are very sensitive, that’s probably why the other one died.

Specifically, hillstream loaches need cooler water than the other fish and fast flowing water, while the other fish need slow moving water.
It looks most like this one


Just to warn you, the tetras need to be in groups of at least 6 of the same species.

What are moulii? Do you mean mollies? If you do, you need to be aware that these are hard water fish while all the other fish are soft water fish.

It’s a hillstream loach, very Friendly and not aggressive. As @essjay said, they need to be in groups or 6 or more.

Welcome to TFF.

I concur with other members here. And before you go out acquiring more fish to enlarge the shoals (groups) of tetras, etc...we should pin down your tank size (dimensions and volume) and the water parameters (GH and pH especially). You may have an issue removing fish depending what we discover.