Please help me identify these strange creatures...

[PGerringer]

Long time lurker, first time poster here.

I set my 12g nanocube up about 5 weeks ago with live rock. About 3 weeks into the cycle, creature 1 shows up. Now that I'm ordering my crabs and snails to add to the tank, there are a billion creature 1s and creature 2 has shown up. Can you please give me an idea of what these creatures may be and if they are harmful for the tank?

Creature 1: Originally they look like little clear rolley-polleys. It looks like they have a tail like a shrimp but the body of a stubby lobster and no claws. They are about the size of a grain of rice and move quick. They don't seem to swim but crawl along the surfaces. I had spots of stringy algae and they seemed to eat it no problem. Who are they?

Creature 2: These are very strange. Imagine cracking an egg and perfectly dropping it onto a frying pan. This creature looks alot like that except the white part of the egg is clear and the sides are pulled close to the "yolk". Also the size of a grain of rice, these thing resemble snails with no shells. They seem to slide along all surfaces and I'm not sure what they eat. What is this creature?

I just ordered the following in hopes they will take care of cleaning the tank. If they have to fight with the above creatures for food, well, Id rather the snails and crabs win.

2 Super Tongan Nassarius Snail
2 Dwarf Blue Leg Hermit Crab
2 Margarita Snail
1 Dwarf Red Tip Hermit Crab
4 Nassarius Snail
1 Scarlet Reef Hermit Crab
2 Banded Trochus Snail

 

[Illuminati]

My Guess

1. Amphipods

2. Stomatella Snails (99% sure of this). Is the inside of your tank glass crawling with them at night?

 

[PGerringer]

1. Will they be fine in the tank or should I remove them?
2. I'm not sure, I also see them slinking around in the day. But, I'll check tonight.
3. Thanks for your answers.

 

[jellyous]

Amphipods are a good sign, part of a healthy ecosystem.

 

[Illuminati]

Check out this site, good pictures for ID's.

http://melevsreef.com/id/

 

[ghostman]

Great descriptions and good answers from Colinadam. Is creature2 clear or snail colored? Is it flat or is there a small shell on top? My first thought was flatworms, but if they have a small shell then I would say stomatella. Keep them, and happy reefing.

 

[PGerringer]

Perfect site thanks! Creature 2 is definitely a "benign" flatworm. Creature 1 looks alot like an amphipod but I'll have to look closer. THanks for all the help.

 

[cherubfish pair]

I woundn't get rid of them. A lot of people pay to get them in their reef!

 

[PGerringer]

Hmmm, now that I know what to look for it seems like I have 3 creatures.

Creature 1: amphipod
Creature 2: flatworm
Creature 3: isopod (the non-pest type)

Sooooo, cool. They should live in harmony with the snails and crabs. Thanks again for your answers.

Edit: Why would people pay to have them in their tank? What benefit do they bring?

 

[cherubfish pair]

<a href=showthread.php?s=&postid=9354457#post9354457 target=_blank>Originally posted</a> by PGerringer
Edit: Why would people pay to have them in their tank? What benefit do they bring?

They're excellent scavengers that can get into crevasses where other inverts can't go and even live in various types of mechanical filters 'cleaning' them.

They also add to the food chain, food for fish, inverts, and corals.

 

[PGerringer]

Thanks again for all your great responses. Now to wait for the package of critters to come. While I wait I guess I'll try to get rid of the 3 bubbles of Valonia in the tank.