Question about hermit crabs and their shells...?!

Question

Hi!

My hermit crab just changed shells. do i keep the old one or throw it away? How many shells should I have in the tank and how many times will a crab change?

Answer 1

Crabs like extra shells just to try on or play with. Best you keep the old one as a toy for him. He may also want to move back in to it just to see which is the better fit. If he keeps the old one, you should get several more.  

Answer 2

They will change shells twice a year at least , or as soon as they grow out of the old one.

1) "As hermit crabs grow they require larger shells. Since intact gastropod shells are a limited resource, there is frequently strong competition among hermit crabs for the best available shells. The availability of empty snail shells at any given place depends primarily on the relative abundance of gastropods in the right range of sizes, compared to the demographics of the population of hermit crabs.

An equally important issue is the frequency of organisms which prey upon gastropods but leave the shells intact. A hermit crab with a shell that is too small cannot grow as fast as hermit crabs with well fitting shells, and is more likely to be eaten ."

"Most marine hermit crabs will appreciate a salinity of between 1.023 and 1.025 (measured in specific gravity), and temperatures between 4–14°C (temperate species) and 24–27°C (tropical species), with a good bed, algae to graze on and a variety of shells to change into. They will happily switch shells frequently if given the opportunity - an interesting display to watch."

Source and further information:

http://en.wikipedia.org/wiki/Hermit_crab

2) "Imagine having to change your house twice a year every year for the rest of your life?

Land Hermit Crabs have to do exactly that. They must change their homes twice a year, because they keep outgrowing their shells.

Land hermit crabs are very fussy about how their shell looks. And scientists have discovered that Hermit Crabs much prefer brightly painted and coloured decorated shells."

Source and further information:

http://www.abc.net.au/creaturefeatures/m...

3) "Younger crabs molt frequently, while older crabs tend to molt only once every 18 months. You should have a few larger shells available for each molting phase."

Source and further information:

http://www.ehow.com/.../...s-pet-hermit....

4) Further information about hermit crabs shells:

- "Hermit Crabs need to change homes when they grow, so you will need to provide your crab with extra shells that are 1/3 bigger than it's current shell, because your crab will grow."

Source and further information:

http://www.thefunplace.com/house/pets/he...

- "A hermit crab will move into a wide variety of seashells. The key is to pick a seashell that has a slightly larger opening then the one they are in now. Some seashells are very large in size, however have very small openings on them. An optimum seashell would be one with an opening just about the size of the hermit crabs large claw."

Source and further information:

http://www.seashells.com/.../...hangings...

- "It is important to keep plenty of extra hermit crab shells similar to your crabs' sizes in the tank at all times. Once a month or so, rotate a few undisturbed shells out with different styles of shells. NEVER buy painted shells! They can kill your crab! See the Warnings for information on what kinds of shells to a avoid."

Source and further information:

http://www.wikihow.com/Care-for-Hermit-C...

- "Invert PSA: Help the Homeless (Hermit Crabs That Is)"

http://other95.blogspot.com/.../...hermi...