Copepod needs identification-cyclopoid?

ReefPodd · Nov 16, 2019

New salt water BioCube32 (17 days) with live rock and sand, dry rock, diatoms developed last week, added a shrimp to ghost feed 1 week ago, now covered in fast moving white bugs on the glass and in the current. Are these the good ones (harpacticoids) or are they parasitic? What fish eat these? Do coral eat these as well or just the harpacticoids?

Lovemyreef2015 · Nov 16, 2019

It's definitely in the order Cyclopoida. Looks similar to a Macrocyclops albidus or a Oithona similis. But these things would be really hard to identify down to a species level. They are not parasitic they are good guys.

Larry L · Nov 16, 2019

@Reef Nutrition

Reef Nutrition · Nov 18, 2019

It looks like a Harpacticoid copepod based on antennae length and what appears to be a single egg mass. A very good organism to have in your tank. Typically, Harpacticoids (3,000 species in the Order Harpacticoida) have a single egg mass that the females carry on their urosome while Cyclopoids (1,200 species in just the Family Cyclopoidae) have 2 egg masses. The urosome contains the genital segment where the eggs are excreted and held until the embryos hatch. This animal in the picture looks very much like a Tigriopus sp., but, because there are many genera and species in the Family Harpacticidae, you would need a copepod taxonomist to id it. Both of these types of copepods are free living, requiring no host, so they are not parasitic.

Hope this helps.

AllSignsPointToFish · Nov 18, 2019

It's Sheldon J. Plankton!

ReefPodd · Nov 20, 2019

I’ve been unnaturally excited about these copepods but my population took a hit after I added a couple of chromis. (Those guys were psyched when I added them to the tank.) If I’m not seeing them now is there a chance that they’re still around in sufficient numbers to make a comeback?

Reef Nutrition · Nov 20, 2019

ReefPodd said:
I’ve been unnaturally excited about these copepods but my population took a hit after I added a couple of chromis. (Those guys were psyched when I added them to the tank.) If I’m not seeing them now is there a chance that they’re still around in sufficient numbers to make a comeback?

Chromis sp. can be voracious planktivores. It's hard to say if the copepods are in the rock and substrate without sampling from those areas. Copepods do a really good job at blending in and occupying very small spaces in the aquarium which makes them hard to detect. Some hobbyists will flash a light in the tank after lights out to search for them.