Red Mithrax Crab

(25 customer reviews)


Only 1 left in stock

SKU: 138.9 Category:


Red Mithrax crabs, Mithrax ruber, are very close relatives to the green emerald crabs, Mithrax sculptus . The red mithrax crabs tend to be more of an offshore, reef dwelling crab, so I think they are actually more suited for a reef tank than the green crabs, which tend to be more of an inshore, non-reef dwelling crab. Both crabs will clean bubble algae, and hair algae, and both will clean other unwanted fleshy macro algae from your tank. You can mix them freely with the emerald crabs and they will get along fine. Maximum size is about 1.5 inches carapace width, and we prefer to ship them at about 0.5 to 0.75 inches.


Additional information

Dimensions 1 × 1 × 1 in

25 reviews for Red Mithrax Crab

  1. Francis (verified owner)

    Arrived in perfect condition and a month later is still pulling out hair algae.

  2. mnewman (verified owner)

    Just got one for my nano tank and now wishing I had gotten several. Very cute little crab that is constantly eating something. Just can’t see exactly what he’s eating. He likes to hide in small area’s like between coral heads. I’ll be ordering several more next time. About the color maroon or rust red in different lights. Expected more brown from some of the previous comments but was very happy with his color.

  3. rebecca.y.tinsley (verified owner)

    She’s fantastic. Arrived alive and well packaged. She’s very fast and started running and picking up food the moment she went in. She is a very good looking specimen.

  4. genevanvoorst (verified owner)

    Arrived healthy and ready to go, will have to see how they do. Nice red color(not brown at all).

  5. dendemereckis (verified owner)

    Best investment! I used to host lettuce sea slugs for algae cleanup, but those would get sucked up into filtration regularly. I received this guy about 2″ across in size, and is very safe and stays in the rocks. Never found him attempting to break out of the house! Very busy and active in the tank on the rocks. I never see him in the gravel. Gets around all between and below the corals just fine cleaning up what there is to eat.

  6. rachelfogle (verified owner)

    I had (HAD being the appropriate word now) a serious bubble algae infestation. I ordered 5 of these guys for my 66 gallon reef tank. In under a month, they have annihilated the bubble algae in my tank. I still have some in spots for them to work on, but the difference is absolutely amazing! And they’re fun little guys to watch too.

  7. robert (verified owner)

    Great crab- just like emeralds and do the same job, but nice to have a little variety. While they are not bright red, mine was definitely red and a good algae eater.

  8. jvcasuso (verified owner)

    Arrived well and ready to get to work. Doesn’t hang out as much as the green but can be seen busily working in the live rock. Nice size and color. Hopefully, it will come out more as it settles in to its new home.

  9. Andy szekeres

    Great crab but the color was not red at all. More of a brown which is fine but was hopping for one more like the picture.

  10. Richard Andres

    I was a little disappointed with the color of the one I got, it was not like the picture, more of a reddish brown, Oh well, still a neat crab for a good price.

  11. Carol Anderson

    Really good size little guy, love the color – nice contrast to the same old green guys!

  12. Sharyn Z Wertz

    Bruce was maybe 5/8th of an inch wide when I got him. He molted after being in my tank just under a month and nearly tripled in size! Super-industrious, with a mountain-man appetite, and a riot to watch to boot.

  13. Cindy E Dailey

    I got two of these guys in this order, they went right to work on the algae. I’ll order more for the other tanks later

  14. Christopher Sanchez

    Somebody had to rate less than 5! Cool crab I will give it that. I have never had an emerald mithrax so I can not compare. I will say it does eat a lot, although it has yet to touch any bubble algae. That is likely because the crab like to remain concealed and my buble algae is limited to the upper exposed areas of my rock. It is very cool though to see his face and front claws in the nooks and crannies. I will be adding a second. Either more visibility or eating some of my bubble algae would have gotten it a 5. – Chris

  15. mark jauregui

    Great little crab started eating the second I put him/her in the tank! started eating my bubble alge down in the first day Ken knows how to treat his customers!!Will recomend him to anyone for great sea life!!

  16. Morgan Hazell

    I ordered three of these cuties, as well as some snails, and Ken really delivered. I was worried because one had popped holes in its inner bag, but as soon as I took it out I saw it was just fine and the double-packaging had kept the little girl wet. I know it is a girl because 2 of the 3 I received were ‘sponge crabs’, holding their eggs under their little wrap-around tails. I drip-acclimated and released them into the tank, and two days later they released tiny baby crab larvae that swam all over the tank, making excellent food for the coral hitch-hikers I received on my live rock. Thank you!

  17. Jonathan Humphreys

    These are great reef scavengers. Really, I’ve never been able to tell a behavior or dietary difference between these guys and the more common “emerald” mithrix. I’ve also never had any aggression issues with these guys, even in a nano tank. I recently ordered 5 of these for my new 120g reef (Ken, as always, sent a couple extra freebies), and all arrived in good condition. Just a great deal on an interesting and very useful animal.

  18. Janie Darlene Lyons

    Cute little guy. Active and healthy. Has a nice pink color under my lighting (actinics).

  19. Andrew Piegols

    nice crab it lives and moves but hides most of the day, maybe traumatized from the move cause it doesnt clean algae that well either, not kens fault, good job anyway.

  20. Susan Murphy

    Love these guys. Have one in a nano tank that ‘begs’ to be fed by climbing to the top of the rock and waving his pinchers. He takes dried seaweed from your fingers.

  21. Tim Taylor

    This is a cool little crab that does a great job of cleaning the tank and is very active.

  22. Lori Walton

    I ordered 1 got 2! They are great little workers, eating from my hand in two weeks! they now come out when I feed and step all over themselves to get the food first! They also get along well with my emerald crabs and other fish. Nice docile crab.

  23. tracey trigg

    Received as promised in good order, with some extra goodies, the folks are very fair sellers..Very pleaased!!

  24. Barry McCool

    Not as red as I had hoped but went to work right away. Truly enjoy them.

  25. Red Angel

    Got two_ one for each tank may order more for Kids tank not aggressive and to big for my Eels to bother went right to work cleaning my wifes algie ball problem and has been seen in my tank feeding on the little peices of meat that float around right after feeding, Pretty and do a good Job… Angel

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