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Spaghetti worm?Please identify.
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Does someone know what this is
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Over 4000 species of marine isopods out there. Had to say which one specifically. Definitely an isopod of some sort.Looking at pics online this may look more like sphaeromatid isopods?
Definitely isopods - for telling if they're good or bad:maybe some isopod?
started noticing these pop up everywhere in my tank.
For the more technical explanation:OP, these are probably harmless, but you can verify that if they roll into a ball (conglobate) when disturbed (like a rolypoly or pill bug; if they do this, they're keepers) and/or by looking at their back half and tail on the topside and underside of the critters (vaulted/domed underside of the tail end is good even if it can't roll in a ball; flat underside is bad and can't roll in a ball).
Yeah, learning to ID these can be a little tricky - I'll link the taxonomic key and stuff to help you figure it out if you want below.
Anyway, generally speaking, there are two superfamilies of marine isopods that can look superficially like this: Sphaeromatoidea (good guys that won't hurt you or your fish) and Cymothooidea (bad guys for our purposes). You can tell them apart by looking at the telson (technically a pleotelson) on the critter; domed (rounded) telson = good, flat/flattened telson = bad.
I can't tell for sure from your pics, but I would guess yours are Sphaeromatid Isopods (A.K.A. Seapills); you may have an easier timer telling in person than I can from pics though (side shot pics of the telson top and bottom would be useful for me).
The key (they do a simplified key for North American isopods, then a technical key for global isopods - I prefer the technical key):
Some resources to help figure out the key (the third link shows some examples of isopods with larger pleotelsons than the first link; the isopods you've got have a larger pleotelson, so looking at both links should give you a pretty good idea of what the pleotelson is even with some variation in size/shape):![]()
American Isopod and Myriapod Group - ISOPODA
ISOPODA Latreille, 1817www.americanisopodsmyriapods.com
And here are some pages with diagrams to figure out the morphology (I like the first and second ones for figuring out the general pieces/makeup of the bodies, but the third is very technically detailed):
Crustacea GlossaryUntitled 1![]()
Isopod Anatomy and Biology - Isopod Site
Isopod Anatomy Mature isopods have 7 pairs of walking legs that are pretty much the same. In Latin, "iso" means "same" or "equal" while pod means "foot". However, isopod mancae (babies) have only 6 pairs of legs in their initial instars. Isopods also have 2 pairs of antennae — one large pair and...isopod.site