HCA: Hermit Crab Association

Not sure what level hermit crabs need. :T

Should I get a 'desert' level like an Arcadia 12% or Reptisun 10.0, a 'forest' level like the 6% or 5.0, or something lower than that?

I figure with their shells they'd need a higher level to get the benefits but I want to make sure.

IvynaJSpyder wrote:Not sure what level hermit crabs need. :T

Should I get a 'desert' level like an Arcadia 12% or Reptisun 10.0, a 'forest' level like the 6% or 5.0, or something lower than that?

I figure with their shells they'd need a higher level to get the benefits but I want to make sure.

I've heard the crabs don't need UVB light? If this isn't true, I'll go get a UVB light today..

ғɪᴠᴇ ᴘᴘs: ᴋᴏᴀ, ᴍᴏᴊᴀ, sɪᴀᴍ, ᴏᴢᴀʀᴋ, ᴀɴᴅ ᴄʜᴇʟʟᴀ

UVb lighting is actually pretty debated. While some swear that the crabs seem to be more active, other's say it has little to no affect. What I do know is that it is very hard to implement with the humidity of our tanks, as plastic, glass, and mesh filters pretty much all of it out. Crabbers have tended to have issues adding them without the crabs being able to get to them as well. Plus, it can be pricy. At one point I was considering trying to add the UVB, but I just couldn't figure out how to make it work without having the crabs be able to get to the unit.

Rawrgeous wrote:UVb lighting is actually pretty debated. While some swear that the crabs seem to be more active, other's say it has little to no affect. What I do know is that it is very hard to implement with the humidity of our tanks, as plastic, glass, and mesh filters pretty much all of it out. Crabbers have tended to have issues adding them without the crabs being able to get to them as well. Plus, it can be pricy. At one point I was considering trying to add the UVB, but I just couldn't figure out how to make it work without having the crabs be able to get to the unit.

I don't know if this is effective at all, and I haven't thought about this until I saw this post but I have my crabs across the room from a window, and at a certain time of the day, I open the window(including the screen, so that there is nothing blocking it) and sunlight comes straight in, but reaches only one side of the crabitat. Is this a fine way of providing natural UVB?

ғɪᴠᴇ ᴘᴘs: ᴋᴏᴀ, ᴍᴏᴊᴀ, sɪᴀᴍ, ᴏᴢᴀʀᴋ, ᴀɴᴅ ᴄʜᴇʟʟᴀ

I use UVB on all of my tanks. You want tropical - not desert. Crabs live by the beach - which is tropical climate. My reasoning behind UVB is I try to mimic their natural environment. I do also have Straws. Straws do require UVB.

I personally like Reptisun bulbs. The type of bulb depends on the distance between the light and the sand.

UVB doesn't penetrate through glass. UVB bulbs also need to be changed every 6 months to be effective.

Not to hijack the post at all, but when you have time would you mind sharing at some point how you have your UV set up? I'm always so unsure about how to go about rigging it.

I just recently put toppers on my tanks, so I have to figure something new out. Before the toppers, I would just prop the front part of the lids open during the day, pop the lights where the lid was open, drape press n seal around it, and be on my merry way. Not once did a crab try to get out. Now...my crabs do have their own room, so I never had to worry about my kitties or dogs getting them if they did.

I don’t use UVB, and it’s certainly optional for usage.
You can really use any plain lighting, as long as it’s not a basking bulb or one that will produce lots of heat. You can use incandescent which does produce some heat, but it’s really optional, IMO.

Currently, I am using fluorescent hoods on my tank, but may be using a reptile lamp with tinted bulbs soon.

The really good bulbs like Arcadia and the T5 HO Reptisuns are strong enough to use overtop screen lids. Regular UVB fluorescents are not nearly as strong and a larger one may be required.

I would go with a 5% or 6% for most tanks. If there is over a foot of distance between where the crabs are and where the light is (on really tall tanks) then the desert strength may be a better choice.

Like others have said, it isn't a must have like it is for reptiles. We don't even know if the UVB physically effects them since they have exoskeletons and don't utilize vitamin D in calcium production. BUT those that do use it seem brighter and more active crabs. It may have something to do with visible light, as arthropods can see farther into UV and IR than we can.

I use the T5 HO Reptisun bulbs.


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Thanks for the info! I have an extra Reptisun 5.0 so I will use that.


I think I will have to mount it inside the tank since I'll have partial glass top covers to keep humidity in... That should be a challenge o_o Maybe I can attach it to the center crossbar thing...

IvynaJSpyder wrote:Thanks for the info! I have an extra Reptisun 5.0 so I will use that.


I think I will have to mount it inside the tank since I'll have partial glass top covers to keep humidity in... That should be a challenge o_o Maybe I can attach it to the center crossbar thing...

The humidity might mess it up