Once again, what's the general rule of thumb....

[Guest]

...as to how many crabs you can keep in a tank without there being overcrowding and ill effects to the crabs. Is it for small to medium crabs one crab per gallon such as say at the most 10 crabs in a 10 gallon tank. And that number would decrease with the size of the crab, correct? Such as large crabs maybe only two or three to a ten gallon tank and ideally large and jumbo crabs should be kept in larger tanks suchs as a 40 gallon breeder or 55 gallon tank...is this correct?

[KittyCaller]

The problem is that it can't be really standard since it depends on toys, and levels and such in the tank. However, I've had as many as 8 golfball sized and under in a ten gallon with no problems. I'd say a gallon to a crab for a small is probably fair, yeah.

[Aviate]

Honestly? I have what most people would consider to be too many crabs in my tank. However, 50% of them are true micros. And many are smalls. I also provide a gazillion vertical and horizontal climbing objects and hiding spots.Ive only EVER had one shell fight, and that was when I had two molting micros in iso... go figure, must be doing something right. I think stimulation and security (climbing objects, and hiding spots) is such an important issue, since as Gaby said, theres no way we can provide a 100 mile full beach for them. Its Jumbos we have to be careful about.... as opposed to "# of crabs" which can differ depending on their size and the way you set your tank up. They all need room to be "alone" when they want, we dont want them feeling aggressive because theyre overcrowded. However, its hard to make a hard and fast rule without considering sizes. I think a lot of the reason people put a "rule of thumb" is to be sure newcomers dont stuff 100 crabs into a KK, more than for people who have experience who can use their own judgement. I am sure whatever youre doing with regard to crabitat populating is right Hoddy- you have good success with your tank.

[Guest]

quote: I think also what is important to consider is how much time the hermies are allowed out of the tank to roam about and such in a "playground" type situation so they can get some more exercise. It seems some of the crabbers here who have smaller tanks do get their hermies out on a regular basis and let them stretch their legs, which I think is great. Although, for purposes of this discussion, if one is regularly removing their hermits from the tank to stretch their claws, there's not enough room in the tank.I believe that the size of the crab plays a big factor. Think of the difference in living space for a jumbo vs. a micro hermit... I have a 55gal tank, and one jumbo is enough, perhaps not even enough for as much floor space he covers when he's walking (although I do have a second level and plenty of things to climb); however, he lives among a half-dozen micros, who must feel like they live in the Astrodome with as much room as they have. If one only has a 10-gallon tank, a jumbo probably isn't a good fit.

[JediMasterThrash]

I've posted this several times before, but all the old posts from the old forum are still in limbo somewhereBasically, each crab needs room/individual space for the following: digging/burrowing, hiding/resting, and climbing.As a whole for the tank, you also need 2 water bowls (saltwater and freshwater) and a food bowl.So, take a look at your tank after you've got the three bowls in it. The rest of the floorspace is currently substrate. You'll need room for at least 1/2 of the crabs to be buried at any given time, and for their burying spot to not be overcrowded itself. I first suggest not placing any of the bowls in the corners, because crabs like to bury in the corners (actually they like to bury up against something, which would be the corners, sides of tank, and sides of deeper bowls).That's a starting number. Now you need to add playthings/hidey places/climbing toys/decor. After you have all your decor in, you need to make sure that there is room for every crab to hide and feel secure. This could be inside of a plastic cave or log, behind some cork or cholla, or amongst the leaves of a fake vine.Between these two things, you should be able to get a good feel for how many crabs you can fit comfortably in your tank (and what sizes).One last thing is the depth of the substrate. The substrate should be twice as deep as the biggest crab. So you need room in the tank to have 6in of substrate, and still have enough height above that for crabs to climb decorations, so obviously a 10g isn't tall enough to accomodate jumbos.You can use these three things to gauge how overcrowded you are on your own, and how many crabs you think you can get before upgrading your tank. If you want to get more crabs, look at your tank, and see if you can find a spot available for him to hide, and see if you can pick an unused spot of substrate that he could dig in. If you can't find these places, then your tank isn't big enough for more crabs.Now, for rules of thumb, here are my observed limitations.Going by size of shell:Teeny = marbleSmall = quarter-50c pieceMedium = 50c piece-golf ballLarge = golf ball-tennis ballJumbo = baseballThese are my sizes. There is no widely held consensus on what constitutes different sizes.Any crab medium and above needs deeper/weighted water bowls, because they'll topply them when they dig if they are too light.5g: teenies only.10g: 2 large OR 4 medium OR 6 small OR 8 teenie20g: 3 large OR 6 medium OR 9 small OR 12 teenie30g: 4 large OR 8 medium or 12 small OR 16 teenie40g: 5 large OR 10 medium OR 15 small OR 20 teenie55g: 2 jumbo OR 6 large OR 12 medium OR 18 small OR 24 teenie75g: 3 jumbo OR 8 large OR 16 medium OR 24 small OR 32 teenie92g: 4 jumbo OR 10 large OR 20 medium OR 30 small OR 40 teenieThe tank needs to be at least 24in deep before I'd put jumbos in it, since they need 6in+ deep substrate, and big stuff to climb on, and not have the stuff they climb on reach the top, since they are strong enough to push open the lid and escape (ask Christa!)If you have a good second level, you can increase these numbers by 50%, since there is more second-level space to crawl and hide in, and with some of the crabs on the second level, there's more open substrate space to dig in.Also keep in mind that if you want to avoid regular baths (and many experienced crabbers believe regular baths and flushing their shell-water are too stressful), you'll need to have water bowls big enough for your crabs to wade in, and submerge their shell. And the water bowl needs to have some method for smaller crabs to crawl back out once they get in. Sponges work great, but plastic mesh or coral are other good options.I personally find that in order to have water bowls big enough to allow self-bathing, you'll need to have at least a 30g tank with a second level, or a 55g tank. So I can't personally recommend anything smaller than that. These poor crabs used to have free reign of the beach and mangroves, it's not fair to keep them in a tiny cage all their lives. Smaller tanks do make good ISOs however.Also, if you give your crabs exercise external to their tank, or give them regular baths, never dig up buried crabs to do this. Only take crabs visible on the surface. I also recommend that you don't deep-clean more often than once every 3 months, to give your crabs a chance to bury and destress/molt without being disturbed too often by being dug up, cleaned (crabs maintain the salinity and acidicy of their shell water, cleaning it out before a crab molts is not a good thing in this crabber's opinion).