After initially thinking it was a crab due to some possibly erroneous information on a vendor’s website, I realized I found my first sea spider. He measures about a centimeter. Despite my revisionist inclination to nurture what others consider harmful pests, I quarantined him and will probably keep it that way.

I succumbed to another half off corals sale at Aquarium Depot when I saw they had some torches in stock. I also added some more types of mushrooms. When I got the shipment notification Wednesday evening, I was surprised to see they shipped it overnight again and wondered if it was a new policy or if it was due to my having had a bunch of deaths in the first order they shipped by USPS, from Florida.

Upon arrival, I filled a 5 gallon spare tank with water from the main tank and temperature acclimated the creatures. Then I put all the coral plugs in a test tube rack and soaked the whole thing in a 5 gallon bucket with about 2 gallons of a solution of Two Little Fishies Revive Coral Cleaner and a combination of clean saltwater and water from my tank. I didn’t bother with a circulation pump this time, so I manually dunked the apparatus a bunch of times before rinsing with a squirt bottle of deionized water. That process removed a surprising number of long stringy worms and various sized pods. Then I put them in the quarantine tank along with the feather duster worms aside from the one with neon green water, which I kept separate (he survived, initially, but then was attacked by a bunch of crabs).

That night, I noticed a strange critter floating around. It looked like a baby version of this guy Aquarium Depot markets as a “red spider crab” for $50:

Mine is not red, though. Not yet, at least. I searched for “red spider crab” on Google Images and found nothing matching the Aquarium Depot image, so perhaps they named it themselves based on its apparent similarity to some arrow and decorator crabs.

I spent some time the next day photographing the critter, and hoped to also photograph a little anemone as well, but I ran out of time. I used my Nikon D800 first with a Tamron AF 90mm f/2.8 Di SP AF/MF 1:1 Macro Lens and then with 4x and 10x objectives on my microscope lit by my exceedingly crappy AmScope 6 Watt LED Dual Gooseneck Light.

I found a pycnogonid, or sea spider, in a batch of small corals and algae. It apparently survived the wash stage, unless it caught a ride inside a tube worm. I'm not sure what I will do with him, as he might prey on corals.

I found a pycnogonid, or sea spider, in a batch of small corals and algae. It apparently survived the wash stage, unless it caught a ride inside a tube worm. I'm not sure what I will do with him, as he might prey on corals.

a pycnogonid, or sea spider

a pycnogonid, or sea spider

The pycnogonid legs are so thin they are supposedly comprised of a single muscle cell. This particular leg is about 70 micrometers wide.

It seems I really should keep this guy out of my tank, as he probably arrived on whatever coral he likes to eat and would like to continue eating. I’ll see if I can keep him alive for a while, though!