I was reading through the libray and do crabs need UV light to survive?

[Horsejazz34]

I was reading though the libray and somthing said UV light was good for the crabs? I'm new to craning and is this nessary for their survival.

[jenok]

how important are day/night cycles uva/uvb light crabs reaction to lightHere are some links in the archived library relating to your question. In answer to your question the light seems to be beneficial but not 100% required. I have had my crabs for over a year without added light and for now they seem to be fine. However that being said I would suggest getting lights at your earliest convenience as I plan on getting some at the end of the year when I upgrade my tank.

[Crabber85]

I am going to disagree with jenok just a little here, I believe that UV light is beneficial and also critical to molt success and the overall health and well being of the crabs as they are much like reptiles in the sense that they need the UV exposure to create their own Vitamin D(this is not a true vitamin its actually a hormone all living beings make in our bodies in the presence of UV light), the hermitcrab needs to be able to make its own Vitamin D hormone so that it can readily absorb the calcium that we provide and no the Vitamin D substitute in their food is not the same as what they produce themselves its a synthetic and doesn't do the job nearly well enough to have any benefits to it at all.I've been using an overhead full spectrum light source for years on my hermitcrabs and their overall health, color and well being has improved drastically since introducing a UV light source into their enclosure.Statistically a wild hermitcrab living in its natural environment is exponentially healthier than its captive counter part because its getting a daily does of UV light, a solid diet, lots of exercise and a good 12 hour day/night light cycle which all helps to improve molt success, color and general well being unlike the poor crab at the pet store which has had a completely inadequate commercial pellet food stuffed down its throat, no real light and horribly cramped living conditions these crabs are going to be paler, live shorter lives, have harder times with molts and ultimately will be sicker and shorter lived than their wild counterparts.Some here may see UV light as an un-necessary element to the crabs 12 hour day/night cycle but there are also just as many of us who see it as a critical must, I guess its just a personal preference.

[Horsejazz34]

I have a uv light bulb heat lamp but people have said not to use it on my ten gallon. I don't have another source of it and what else is there to use?

[Crabber85]

We typically recommend using either the Repti sun 5.0 or 10.0 florescent tube style as it puts off very little heat but does a great job of radiating the UV light required by hermitcrabs so it can easily be adapted to any tank size. The fixture and bulb can be bought together at places like Petco or Pet-smart in a combo kit for around thirty dollars.The florescent tube style bulbs aren't the best choice for UV light broadcast because they tend to only last for six months before loosing the ability to give off UV light.You can get away with using the bulb and fixture you have now but it will need to be about two feet away from the tank and since UV can not pass through glass ie: glass like automotive, aquarium and home windows are designed to filter out a large portion of UV from natural sunlight as a means of protection so the UV source will have to be shined down from overhead through an open area so that it can pass through into the tank.Plastic is also another excellent UV filter so if you have your lid wrapped in Saran Wrap or Glads Press and Seal your still going to be filtering out a huge portion of the UV light.

[jenok]

Guess I'm still learning new things. I don't recall reading anywhere that they needed it for help with the molting process. I did read that it made them more active. It just seemed like one of those things that if you didn't have the light or money to get one they would still be ok judging by my experience and in some of the responses to those links.That being said I do have them in a room where there is a lot of natural light coming in and even though the windows filter out most uv I guess they still get some.

[Crabber85]

@jenok, between the window and the glass of the aquarium the crabs are likely getting less than 0.5% of the possible UV they could be getting from the sun so in other words its so negligible at this point that its not really doing much good I'm afraid.Theres been a lot of anecdotal evidence that suggests that hermitcrabs benefit from UV-B exposure as it helps with molts, causes deepened exo coloration and improves overall health.Hermitcrabs like most crustaceans see in the UV range so they literally see what the human eye can't and that helps them to know when its day time and when its night out in the wild which is why black light bulbs are a bad idea for night time heating because these bulbs produce UV exclusively due to the way they are designed which can really confuse reptiles and hermitcrabs because they will see this UV light and think its day time all the time.Personally I've tried using a black light bulb for overnight heating years ago and it really did mess them up they were hidden the whole month that I used the bulb and then it hit me the only thing I'd changed was the bulb so I replaced it with a moon glo and they went back to normal, it was really weird.