Those are Boraras species fishes... looks like you might have 2 variants, the Boraras brigittae (deeper red color with black stripe) and Boraras merah (less red color with black oval patch). Note that the ones in your photo are relatively young juvenile ones, they will still grow abit larger over time.
Anyways, those boraras fishes could help to eat mosquito larva (depending on the larva growth stage, early instars are usually small enough to be eaten, later instars may be too large), along with other tiny critters too. But due to their smaller size, they may not be able to consume all the larva in time (especially if there are alot of larva and few fishes), so you may need to stock more of the fishes or continue monitoring the tank and physically netting out any larva that manage to escape.
They will snack on some newborn shrimplets though (shrimplets and mosquito larva are similar size), so thats a trade-off. But if there are sufficient hiding places in the tank (ie. lots of plants, hardscape etc), a percentage of the shrimplets will usually be able to hide and survive long enough to grow larger and not get eaten.
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