Hi, Rolycrab! So glad to see you're doing your research
before bringing home any crabs -- they'll thank you for it
.
@soilentgringa nailed it in her post above but I'll add my 2 cents worth, too.
Re size of tank. The answer is always get the largest tank you can afford if you're intending to have more than one crab. You'll be amazed at how quickly they grow when they're in a nurturing environment! At $20, the 20g is a terrific buy but, for another $9, you can get a 29g: same footprint but 6" taller. A mere 6" may not sound like much but it gives you more above-substrate space to provide climbing items, very important for crabbie contentment. BTW, the Petco $1-a-gallon sale runs through August 8th in most areas and is held 3 or 4 times a year.
Re UTHs. Yes, they attached to the outside rear wall of the tank and should not dip below the top of the substrate by more than an inch (you don't want to dry out the substrate while providing warmth). Assuming a
minimum of 6" of substrate, you'll want a UTH that is 11x23 for a 29g or 6x23 for a 20g. The next length after 23" is 35", too long for the 30" length of the 20/29gs. I have 7" substrate in my 29g so the 11x23 UTH just meets the top of the substrate; the 7" length difference between the tank and the UTH allows for a slight dip in temperature on one side of the crabitat, offering a cooler area for "chilling" out (I keep the moss pit on the cooler side and the guys love hanging out in it).
Re buying cocohuts and other decor: remember that store-bought decor is for
our pleasure, not the crabs'...they don't care what the hide, dishes, pools or climbing items look like
! You can make a nice hide using an empty plastic butter or yogurt container: just cut out an entrance, flip it over and, voila!, instant no-cost hide. Plastic or fabric plants and vines can often be found at thrift stores (Goodwill, St Vincent de Paul, Salvation Army) and dollar stores so you don't need to buy the pricey reptile ones at pet shops. Pools can easily be made from small Tupperware containers or plastic containers from the dollar store (usually sold in 2,3 or 4 packs for $1 or $2). Eggshell halves make great feeding bowls, especially when your crabs are small. If you have access to small branches from safe-list trees
not treated with pesticides (i.e., from the property of a friend or relative who knows for sure whether or not pesticides were used), you have no-cost climbing materials. The one decor item I would suggest buying is used fishnet, available in craft stores such as Michael's and Hobby Lobby: the bagged piece is large, about 3'x5', can be easily cut to fit along the tank walls or draped to make a hanging shell shop or crab hammock (you'll need to rinse the netting in super hot water - no soap, of course - to get rid of debris and fishy smells). Hermit crabs simply love climbing and sleeping on fish net!
A serious suggestion: install corner guards in the crabitat! They are
perfect for attaching vines, netting, hanging baskets, etc., without having to use unreliable suction cups! All you need for a 20/29g tank is one L-shaped 4' x3/4" strip of plastic corner guard (called "wallpaper guards" and found in Home Depot or Lowe's Blinds section for under $5) and a tube of aquarium silicone (also in Home Depot/Lowe's for under $5). Cut the strip into three pieces (to fit under the inner tank lip, back and both sides), drill small holes along one side of the L (large enough to accommodate a plastic cable tie -- packs of 100 4" length about $4 at Home Depot/Lowe's), then attach the undrilled side to the inner tank wall, drilled side jutting out below, with the aquarium silicone. The silicone needs to set and the smell diffuse so you'll want to do this several days before you add the crabs to the tank.
While you're in Home Depot or Lowe's, pick up a 50lb bag of playsand (found in the Concrete section, about $5). For a 20/29g tank, all you'll need for a 6-7" substrate is one bag of playsand and 3 bricks of compressed EcoEarth (3-pack about $10 at PetSmart). If you're planning on using only playsand, buy two bags.
One last thing: as you know from scoping out the HCA site, crabs can eat what we eat, with a few exceptions (Safe- and Unsafe Food Lists), so don't waste $$ on commercial hermit crab foods. Just be sure to pick up a box of Instant Ocean and a bottle of aquarium dechlorinator (API Betta Water Conditioner is cheap and removes ammonia as well as unhealthy minerals such as chlorine) to prepare the FW and SW bowls/pools.
Hope this long-winded post helps
.
