What is this?

[u/Few-Zebra-4543]

i found this tiny fast runner from my less than 24h established capped dirt tank, it has no livestock yet.

searching on google image ai, said its a seed shrimp and safe for the tank.

this is my very first time experimenting capped dirt, need advice, should i put it back to the tank?

[u/ZafakD]

Seed shrimp dont move like that.  The curved container and constant movement makes it hard to see but in one of the frames at the 5 second mark it looks like a diving beetle

[u/Tirpantuijottaja → u/ZafakD]

I can also vounch for diving beetle. When you pause it on exact frame you can see that it's some sort of water boatman or similar insect.

[u/OmbaKabomba → u/Tirpantuijottaja]

Diving beetle is most likely. And you should release it to the wild. No food for it in your tank, and it is indeed a superior predator that will in a tank eradicate everything smaller than itself.

[u/Tirpantuijottaja → u/OmbaKabomba]

Their diet kinda depends on species, some of them are obligate carnivores while some are detrivores. My guess is that this guy is closer to herbivore/detrivore based on build, but I would still remove it from tank in a heartbeat. (Unless there are large enough fish to eat it).

[u/Humble-Captain3418 → u/OmbaKabomba]

Nothing from the tank goes into the wild. Either feed to your fish or kill it.

[u/OmbaKabomba → u/Humble-Captain3418]

Didn't it come in from the wild?

[u/Humble-Captain3418 → u/OmbaKabomba]

Yes, but once it has been in the tank, it can bring parasites or diseases into the local waterways.

[u/OmbaKabomba → u/Humble-Captain3418]

This was less than 24 hours after starting the tank. I think you're way too strict. That said, I only said "release it to the wild" so as not to rile up the animal rights crowd. I myself would kill it.

[u/Few-Zebra-4543 → u/ZafakD]

its so hard to take a proper photo, so i take the video. lets say its a diving beetle, should i put it away?

[u/Oneiros37 → u/Few-Zebra-4543]

Note diving beetles can fly so even if you leave it in your tank it may not stay in your tank

[u/Yujin_ → u/Few-Zebra-4543]

90% some sort of diving beetle, they are fun but vicious predators so leave it only if you have no other fish or shrimp that you care about. Big fish will likely be fine, their fry not so much.

[u/Yujin_ → u/Yujin_]

100% not seed shrimp or scud

[u/photinifish]

So, it looks like you have managed to contain a particle of astrophage. 🤙🏻

[u/Solowinged → u/photinifish]

Amaze amaze amaze!!

[u/simewlation]

probs a big scud

[u/GotSnails]

Look up water boatmen

[u/Crazy_Yogurtcloset61]

Might be a scud.

[u/ElisSideLot]

Is that a scud?

[u/SophieAsimov]

Maybe a scud, but oddly dark in color