500 gallon vivarium, how many frogs?

I'm jumping in late on this but large tanks are one of my favorite topics. I think there is much more to think about than numbers of frogs and some of this was discussed with sustainability. With a tank that large, you may have the opportunity to observe frogs at close to natural densities. If you you figure a square meter of territory per frog in the wild, then you would be looking at maybe 3 frogs in the tank. You could probably push that to 5 frogs and still have a fairly sustainable tank. If you stock the frogs at densities close to what is found in nature, then you have a really good chance of being able to produce enough plant biomass to support the insect biomass to support the frogs. Justin's suggestion of adding rotting fruit is a good one which would boost the tanks ability to produce food insects but I don't agree that you would have to sacrifice aesthetics. A tank that size could easily hide a few oranges or bananas without ever being visible. Also, you can always toss some leaf litter over the fruit which I think actually enhances the aesthetics because what you see is little insects crawling around in the leaf litter as you would in nature and you get to see much more natural feeding behaviors by the frogs.

As for specific recommendations, I would start with a single species and only add a few frogs. I would actually add no more frogs than you would put in a 20 gal. tank. You can always add more frogs later if you like but again, stocking the frogs at very low densities would give you the opportunity to observe things that are not possible in smaller tanks with higher densities. I personally don't have any problem with someone starting with a very large tank for learning dart frogs. IF you can produce the food volume you need to seed the tank, then you will find the volume of the tank very forgiving. As far as mixing species, you would probably be able to do it successfully in this size tank but I wouldn't do it right off the start. I think it's really important to learn each species you keep individually before mixing so you can more easily recognize signs of stress or abnormal behavior.

As far as seeding the tank, I would seed it with some good forest loam. That is going to provide the highest diversity of soil arthropods you could hope for. You might get a few undesirables like snails or millipedes but in a tank that size, I wouldn't worry about it.

If you do decide to mix species later on, it is important not to create hybrids as others have mentioned. Basically, you don't want to mix species within the following groups: tinc group (auratus, azureus, leucomelas, tinctorious, glactanotus?, castaneoticus?), Phyllobates group, histrionicus group (granuliferous, histrionicus, pumilio), and the quinquivittatus group (imitator, ventrimaculatus, reticulatus, fantasticus, intermedius, and the many similar species). That's a quick list off the top of my head so I'm sure I left many out.

Justin, Brent, Brian, Landon et. al.,

Thanks for all the good advice. Here's the update so far. I 've decided to use the forest loam, together with some mosses I've rescued. I hope this will provide plenty of arthopods and insects for some native plankton.

I've been collecting plants and forest loam and mixing it with leaf litter for my soil. Soon I'll be making my own soil from sand, dry manure, peat moss and potting soil. Vivarium Concepts has been generous in helping me with viv design. Some of the design ideas right now are putting a cliff in the middle of the tank, givng me two more surfaces to plant on while caves and holes allow frog passage, and planting dendrobium orchids in a miniature "forest". I don't know how many water features I will have yet.

For species, I'm going to start with leucs until I gain more experience, or until my impulse upon seeing a new frog makes the money jump right of my pocket. If I can resist my impulses to buy the pretty specimen if front of me, I may progress to this kind of order: leucs, auratus, galacs, terrribilis, pumilio. But knowing me, in a few months my frogs list will probably be completely different than this list.

Soon I'll post a "before" pic of a cleaned out reef tank.

Dave

Well, i have had some experience with setting up some pretty large enclosures, in the middle of setting up a 150 azureus display....i think that you are wrong in saying that Dave has no experience....i would argue that someone with a few years under his belt in reef keeping has a huge headstart even over someone who has kept darts. There are some very important rules in animal husbandry that supercede individual species experience. Like Brent has mentioned before me, this tank could be a rare opportunity to observe these animals in close to natural densities. So, on the contrary, I think that this could be an opportunity to "really" see these frogs. I would personally not hesitate for a second to build a tank this size and If it were me I would probably follow Brent's suggestion and go with one species of dart and really watch them. You have great opportunity to build a tank that would support all elements of the frogs reproductive behavior and can be accomplished with minimal energy input (atleast food input im sure it will be a pretty penny to light this puppy). Raising frogs in a 10 gallon and raising them in a 500 gallon will show a vast difference in potential insitu prey establishment. My best advise is use what you have learned from your reef hobby as much as possible, look at the frogs as an accent on the whole system and you will be rewarded greatly. Ben

oh something else that has not been mentioned is the lighting situation...with a tank that shallow you may have lit with straight compacts but maybe you had some MH as well....what are you running? something to think of now is a good way to cool those lights, fish tanks are a bit more forgiving as far as spreading and dissipating the heat....ben

Sorry k2bordr03 I'm going to have to agree with Dave and a few others comment. This is a very unique opportunity and will make for a spectacular conversation piece. True, fish are one thing, but saltwater fish constitute a whole world of maintenance issues. If Dave has been able to hold his own with salt water, then I am sure he is patient enough to learn the tricks of the trade for darts. That being said there are a lot of tricks to learn. Just stick with this board and I think you'll be very happy.


Dave-

I'm going to be finishing up my degree in landscape architecture..having said that I guess I don't have to explain my obvious love for plants. I work in the greenhouse at Rutgers U. (aside from selling my soul to this college) and would love to support your "little" project with a few plants if I make it down to the meeting. I have some larger bromeliad species that I think could go perfect as some larger specimen piece in the tanks landscape. Let me know if you are interested..if I make it down I'll be happy to bring some.

Best of luck,

Mike C.

azureus
yellowbacks
citronella
leucs
lorenzo
patricia
vents
intermedius
imitators
bastimentos
almirante
bruno
retics
golden mantela

and a partridge in a pear tree

K2bordr03, Ben and Mike C.

Thanks for the input and critique. Reef tanks taught me to keep a high ratio of natural food to stocking density, and I think this theory transfers to frogs. True, I will not see darts as often as in a small tank, but it's nice to know that their behavior in such an ecosystem (even hiding behavior) is closer to their natural behavior. And the opposite may happen, darts timid in small enclosures may roam more freely given the space. Only time will tell.

If I keep fruit and feeding dishes in the same places, I hope the frogs will come into the open. Nor do I think food will be so expensive, I calculated a homemade brew of FF media (substituting carrot juice and peaches for water and applesause), and a gallon jug of media cost 50 cents.

Ben, because the tank is in an open closet the two 250 watt metal halides don't build up heat as if they were enclosed in a box above the tank. Also, the sump is located above the tank and the metal halides warm the sump water in my cool basement without heaters. The large surface area of the sump causes a lot of evaporation. I use sodium lights there for a plant growth refugium. With the reef tank I used a 4" fan only in summer, but only experimentation will let me find optimum venting.

Mice C, thanks for your offer of plants, I'll take the help and compensate you for the time. Alex at Customecos just purchased a greenhouse full of miniature orchids and I will place a big order with him sometime after the Christmas rush. I've also been an avid gardner for years and think another gardening theory applies here --"Grow good soil and the plants will take care of themselves". In this case, I hope a good viv is insurance for having good frogs, presuming I follow the rest of the good advice on this board.

Sorry for the long post.
Dave Willmore

k2bordr03 said:

I hate to burst your bubble, but a 500 gallon viv just isnt realistic for you. you might have had fish in the past but dart frogs are a whole new world. even if you could culture the springtails and enough food(which would be tons of cash for a tank that size) you havent had any experiance with these animals. that is the key that you are missing. Even some of the most avid keepers dont keep over 250 gallons.

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I really disagree with this. I'm just curious about how many people who think that a very large vivarium is not practical actually have any experience with them? It has been my experience that very large vivaria stocked lightly with predators are MUCH more forgiving than traditional small vivaria. You name the parameter: temp, light, moisture, food, etc. and a large viv is going to provide a lot more choices and more safeguards than a small viv. Large vivs are more diverse so there tends to be a range of temps, light, moisture, etc. compared with a small viv that tends to be uniform. Suppose you get a heat spell. A large viv takes longer to heat up and will retain cool pockets much longer than a small viv, thus increasing the odds the inhabitants can survive the ordeal. Food is no different. It is much more difficult for a few frogs to hunt a springtail population to extinction in a really large viv like they can in a small one. Fruit flies tend to persist a lot longer too and you can set up areas where the ff can actually reproduce inside their viv. My largest viv is only the equivalent of about 100 US gallons but it always has bugs crawling around in it despite the fact that on average I probably toss fewer insects in there than in my smaller tanks. The ability to feed a large viv has more to do with the ratio of predator to prey biomass as anything else.

The only real risks involved in such a large setup are the amount of money spent, and the danger that once it's all set up, you will wish you had done things differently. But as for being able to sustain frogs in there? Piece of cake.