HCA: Hermit Crab Association

WOW, awesome information!! Thank you for sharing all that!!

I do have a question though. A crabitat is nothing like a fish tank when it comes to measuring nitrates and ammonia levels. In a fish tank, we can simply pull out the PH kit, measure and do the weekly water changes if something is slightly off. However, in a crabitat, there is honestly no way of measuring the good versus bad bacteria. If deep cleaning of substrates is not done, but only mixing and aerating it, how could we possibly know what bad/good bacteria is stirring in the sand? It would only be a guess, no?

Ah, but measuring of chemical levels CAN be done in a tank, via a soil testing kit as can be found at any organic gardening supply house, and since we are not talking about a crab only environment, but rather a balanced vivarium environment, as long as we pre-seed with good bacteria and give them a chance to establish, and as long as all the plants and small life forms are staying healthy, we know that we're ok. The thing is, the bad bacteria produce chemical levels that can be picked up by the test kit. As long as your soil quality remains good, then you have a good balance of good/bad bacteria

What a great discussion! I’m not trying to be a nay-sayer, but I just thought I'd present a few thoughts on the other side of the issue. In no way am I saying that partial changes of the substrate are necessarily bad, but there are a few things we should consider before we embrace this method wholesale.

I think that the comparison between fish tanks and crabitats is fundamentally flawed, for several reasons.

First, the fish are actually living in and breathing the water; crabs do not breathe their substrate. Fish who live in water that is never changed succumb to gill disease and infections, because they are in effect breathing their own waste. This is most problematic during the “cyclingâ€

My brain hurts now.

I just wanted to throw in my crab care technique here since this topic closely relates to mine. I have already reduced my methods of deep cleaning myself and have seen some much more positive responses then expected.

Obviously I cannot reduce to nothing because I do not have live plants planted. I do not pull out all the sand for a deep a clean though and some cleans are simply a removal of the top layer, crabbie head count, turning of the sand and remodeling the 'tat. Due to my not having plants and other natural benefits like that I am still doing these "half" cleanings about every 4 months or especially when I may notice/sense there's a troubled crab.

I really hope this makes sense. I basically just wanted to mention that I do not pull out all the sand bake/replace and wipe off the tank with a cleaner everytime I deep clean.

So with just that little statement there said I think I should stop. HAHA I just hope something I've said has made sense.

KCGirl- Excellent points all. Allow me to respond. While I will cheerfully admit that crabs do indeed not breather their substrate, they do spend the most delicate parts of their lives there, namely, while molting. During that time period, the wastes and bacteria in the tank fundamentally affect the outcome of their molt, thus, it is just as important that the environment be safe as it would be for fish. I am also not looking at merely substrate when I say "the tank", I mean the entire environment. Thus, since the composition of substrate is one of the MAJOR factors in molt health, as that is when bacterial infections, death by toxin, and so forth occur, I do feel that it is just as important that they have a healthy substrate.
Water changes are indeed to remove bacterial concentrations and waste. Waste in an organic sense means the excretions produced by an organism, and that is what the nitrates are. The nitrates are a toxin in that they are a substance that is substantially harmful to the other organisms in the system. The toxins are not inert. Nitrates are toxins. The ammonia may be inert, at least most of it, depending on your tank's chemistry, but nitrates also kill. Also, the good bacteria live all over the tank, not merely in the filter, or even the undergravel filter media. These provide places for certain species of bacteria to congregate, but it is by no means the only place in which they live. And removing harmful bacteria is one of the points of the water change, as it is the bad bacteria's waste products that cause much worse problems than mere nitrates. If all that you are testing for is nitrates and ammonia, you are doing your fish a disservice. There are a great many compounds present in a fish tank, and many of them can be harmful.
I do believe in substrate filters. I call them plants. Just as mangroves and macro-algae provide natural means of nutrient export, removing things such as nitrates and the dissolved nutrients from food breakdown, plants in a crabitat serve the same function. Plants are the ultimate biological filter. I hold that crabs DO need a filtered substrate, as it will substantially help with the bacterial populations that could be harmful during molts, by removing the nutrients from the soil that they would need to flourish.
I agree that one can do massive water changes. The problem is, as you say, the shock to the fish. I never said that the shock came from having clean water, in fact, if you read my post, you would see that I said that it was NOT the new, clean, fresh water, but rather the sudden shock due to pH, temperature, and water hardness, just as taking crabs out of a nice cushy crabitat, putting them in a temporary holding facility, and then putting them back in a tank that now smells completely different and is all rearranged proves a shock. I completely agree that it is the biological filter crash and the dissimilar water parameters that causes the problems, as I said in my original post. I also agree that it is the change in conditions which causes crabs to have stress issues during deep cleans. Both of those were points that I made in my original post, and thus, I ask why we should subject them to those stresses, when it isn't necessary to remove them from the tank at all.

On your third point, I will MOST strenously disagree. Nothing can live in an actually sterile environment. We require bacteria in our guts to digest food, bacteria on our skin to handle environmental toxins, bacteria regulate just about everything for most forms of life on this planet. Allow me to suggest that with adequate biological filtration, 100% changes would not be necessary. Look at the example of the mangrove refugium, in which mangroves, macro-algae, and detrivores are used AS a filter for a main tank. The water in the refugium remains clean, with minimal changes required. I am not saying that the people who keep betta in unfiltered smaller than optimal conditons are bad people, but, personally, all my betta live in minimum 2.5 gallon planted filtered aquaria, and I would never put so much as a shrimp into an unfiltered tank. I use sponge filters for minumum water movement, since I do agree that filtration METHOD needs to depend on species, but I do not feel that need for filtration changes. Simply because a condition is adequate does not make it optimal.

I again, dispute that a crabitat is an unfiltered or closed environment. First off, there is no such thing as a closed system. Even when we were doing epitaxy in the vacuum trail behind the space shuttles, there was still contamination, much less in a tank in a house. That is the problem. Since we CANNOT maintain a sterile environment, all we do is create a bacterial vacuum, which nature WILL fill. I am not talking about a closed system crab only minimal bacterial system, I am talking about a well balanced vivarium, which is self sustaining. I am talking about large PLANTED, FILTERED water systems, a large PLANTED( i.e. biologically filtered) substrate area, and a background that allows more space for climbing and hiding, to mimic more closely the fact that most hermit crab species are fairly arboreal. An undergravel filter under the substrate, with filter media, and either a filter if you want one or bare minumum drainage capabilities if you don't, so that when the water from the plants drains, it doesn't cause root rot, and prevent the formation of anaerobic bacteria. There are a great many great sites on vivaria that explain the concepts and balancing issues in them.
As far as digging up a new crab, I immediately put ALL new crabs into ISO for at least a month, following fairly closesly the guidelines on coenobita.org. PPS has to do, in crabs, with sudden changes that they cannot adequately process, be it from change to a worse OR BETTER environment. Please check out the article at coenobita.org for more info. It takes them a while to adjust their metabolic functions. With Indos, for example, if they are suddenly dehydrated for a period of a few hours, lung and gill damage sets in. If they are rehydrated very slowly, they can recover, but if you rehydrate them quickly, they die.
As far as seeding the tank goes, again, with the plants and smaller life forms, we have enough material to feed the good bacteria. If you are concerned about obtaining pure strains of individual types of bacteria, and disease free insects, please allow me to suggest a scientific supply catalog, where you can be sure that they are pure sources.
With a well balanced vivarium, all you need to do is mimic the effects of wind rain and other animals by doing frequent small changes and cleaning. Vivarium keeping has been sucessfully done for decades with all sorts of animals, from some of the most delicate of dart frogs, to exotic lizards, to tarantulas. There are many more delicate species that simply thrive in such setups. In my mind, keeping a crab in a tank without live plants and live soil is no better than keeping corals in a tank without anything else, or keeping a betta in an unfiltered 1 gallon container. In all these cases, while we are trying to provide an adequate home for our pets, we are not doing the best by them that we possibly can. Crabs are FORAGERS. Without sufficient things to forage in and around, they lose interest in eating, leading to metabolic issues, as well as difficulties in molting for larger crabs. Please check out my blog, as well as some vivarium sites, for more info
I love this topic, as I find it great when everyone throws ideas out there. I think it advances our knowledge. In my opinion, friendly debate is ALWAYS a good thing

I have never done "deep cleans" for exactly the reasons you stated, and it has worked VERY for me in the past 2 "good" years I have been crabbing, I have not lost any crabs since I have done it this way and I Hopeful will not lost any in the future.

However, My question is, when I setup my 40b (which is a lot bigger than a 20g) I had to buy more sand (I use crushed coral) to fill the tank up to the proper height, I also used my sand from my previous tank to 'seed' it with beneficial bacteria and the like. But, I am wondering if this will be enough to completely seed my tank, since the old sand was only about 45lbs and that combined with the 80lbs of new sand do you think that the amount of new sand would be to much for the bacteria in the old sand to produce the bacteria? Another slight worry of mine is that the crushed coral I get I get by the pound and the coral it's self is in an open bin, so do you think that there would be bad bacteria in the new coral? which might over power the "good' bacteria?

Although it is really not possible to do this set up in a *smaller tank, this new way of thinking appeals to me because EVERY time I do a complete change of substrate I have humidity issues, where my humidity is up and down and all over the place for weeks! I am looking for a more stable way of doing things.

I wonder if the partial substrate change would be ok to do in a smaller tank? -- weither I add the live plants or not... and how would the plants do when it came time to change the substrate around them? Would then then be loose in the soil so the crabs would knock them down and destroy them?

*(in a post, don't remember if it was this one, her blog or on CSJ, Cisnegra mentioned this is really meant for a 40B or larger set up)

I Must agree with Cisnegra. A Deep clean really isnt that necessary unles for 2 reasons that I can think of for the Moment.
1) Mass death due to an Unknown Condition.
2) Bug Infestation of unknown origins.

I have always said that I like to have a Micro Eco system in my Set up.
Beneficial Bugs and Such. I Personally dont have a Problem with bugs. Even Fruit Flies. Yes they can be a Pain. But seriously, are they harming the crabbies??? Prolly not. They are more interested in the Nice foods we offer our "Lil Dudes". Of course, like anything else...."Everything in Moderation".

A Mini Eco System is Best. Bacterial and Up thru to our Organisms Living in the "Re-created" Conditions we provide.
The Crabbies in the Wild are exposed to a Lot of things and they do rather well. But As I said before...We need to keep things in check as we can.
U dont want a Runaway problem. Yes Sift thru the Substrate Periodically to remove the contaminates...Otherwise, try and let things be

Great Post Cisnegra! And I also Agree with ur comment "Friendly Debate" is a wonderful thing for all of us to Learn and Grow by. This is how we Learn from eachother and can better our techniques and caretaking.

*Please folks, Let us Keep this thread Friendly.
I would hate to see somebody get offended.

Silent Protagonist: I'd look at your situation this way. When you set up your original tank you used all new substrate with no/unknown amount of bacteria beneficial or not right? So at least with the new tank you've got an edge with the fact that you've partially seeded the tank with the old substrate. I don't think I'd worry too much about it
Feathers: I don't see why something like this couldn't be attempted in a smaller tank. I think I'd try what you've suggested, partial substrate changes and smaller plants It'd be interesting to see the results.
I wish I had the time/money/patience to set up something like this. Maybe in a few years when I'm living in my own house and not an apartment I'll try something like this At least now I've got some resources!

Silent_protagonist: I would think that seeding with the sand from the old tank would be alright, keeping two things in mind. First, that you would consider the old sand to be "healthy". Second, that you would give it a few days before putting crabs in, stirring it every day, so that the old sand is fully distributed through the new. I would think that that would be fine.
Feathers: Like I said, a 20 should be fine, just make sure to take into account that in the smaller tank, smaller plants will be necessary, as will probably more frequent changes, since wastes accumulate faster in the smaller tanks I have every confidence that you can handle it, you've been at this for a while I would DEFINITELY say put a undergravel filter under the substrate, to prevent root rot, but otherwise, you should be fine
I agree with OIF_VET totally, most things in moderation in the crabitat are a good thing. I also agree about keeping it friendly

I am all for friendly debate. I hope everyone understands that by disagreeing, I am not trying to be unfriendly or to offend anyone; I am simply trying to offer a different viewpoint.

Teresa,
I understand your viewpoint and I am certainly not saying that this method is a bad one. I am simply saying that it is not strictly necessary. I could go through point by point and explain exactly what I meant in each statement. For instance, of course nitrates are toxins, but in small quantities they are not toxic. There is a huge difference. Ammonia should never be present in a cycled aquarium in any concentration. If it is, there is a problem with your biological filter. And of course, beneficial bacteria live on other surfaces of the tank other than in the filter. We could also discuss dictionary definitions versus common usage. But since it is obvious we have both had experience with aquariums, I don’t see the point in debating semantics. Instead, let me just condense it down to a few statements.

First, let’s focus on the comparison between fish tanks and crabitats. Using plants as a “substrate filterâ€

I'm pretty unscientific about the whole thing, but I have set up my crabitat and my other rainforest setups with microorganisms and bugs on purpose by adding forest soil and leaf litter. The frog enclosures haven't been cleaned in about five years, the crabitat was set up about a year ago, but a 20g worked very well for three years that way. I rely on the experience of many German herpers, it's pretty common to set up enclosures with high humidity as "mini eco systems" here.

By the way, OIF, it's good to see you! I haven't seen you around too much lately. Maybe I've just missed your posts...

Indeed, I agree that deep cleans are indeed a valid way of doing things. I even agree that, WITHOUT a vivarium system, they are ABSOLUTELY necessary As you said, my method only works for larger crabitats, which I also pointed out. I agree that the deep clean method is a valid one, just not necessarily the best method. As I said, adequate does not always mean optimal. If all you have space for is a smaller tank, than indeed, you have to deep clean. In my opinion, we should all strive to have large enough enclosures to allow lots of room to forage and play, but, as someone who started with a KK, and then a 10 gallon, I understand that most of us don't start in this hobby thinking we'll be needing a huge tank and lots of equipment I think that someone with experience at nano-tanks would be ok to try a full vivarium in a smaller tank, since they would understand that there is a lot more work to do the smaller it is.
I will also agree that plants entirely by themselves do not an entire filtration system make, even in aquariums using just a mud/mangrove system as a filter, you still need your protein skimmer and usually another form of mechanical filtration. In the vivarium concept, you provide the mechanical filtration, sifting through and removing uneaten food and debris.
I also agree that we could debate semantics all day, and it would make this a less than useful topic.
I agree that a deep clean is a valid method, and indeed, has worked well for many people for many years. I think it could stand some modification, and could stand to be "updated" to reflect all the available information about crab needs, which would mean giving them, if nothing else, more foraging time and space, even if you keep a standard system.
I don't think anyone thinks that you are being less than friendly. Indeed, I appreciate the differing viewpoint being so very well represented, in such a concise and informative manner, since it allows for a much more informative debate

I do a deep clean once a year. I don't totally replace my substrate, but I do add more because through out the year, some of it has been scooped out because of buried food (i remove the substrate around the food to make sure i get any mold out). Other than that, I've never had a problem with mold (with the exception of the time i bought that climbing back ground) or bugs. If all my crabs are up, I take everything out except the substrate and boil everything (every few days, I boil the gravel I have in the water dishes and the shell I use as a food dish). My hermies seem pretty healthy and happy with my method.