I have a huge box of chunks or grey lava rock I got second hand from a cichlid tank. I have sanitized them long ago and I was going to put them in my 29 goldfish tank but decided not to because I was afraid they'd be to sharp for the telescope eyes I love so much. Now I only have a 10 gallon tropical tank. The rock is sharper and rougher than most lava rock I've seen, but tropicals tend to be less klutzy and are a little more airy with swimming. I've got black neons and a honey gourami, and I will probably get some ghost shrimp for fun later. I was playing around and two small peices fit together perfectly to make a mini cave. It would look so neat in the tank, especially with some java fern or moss growing over the top. What do you think? Would the easiest way to glue the two peices together be with aquarium sealant?

The lava will up your ph and I think your ph is quite high already?

Oh yah I totally forgot about that. I have driftwood and my kH is over 300 but I guess the lava and the driftwood together could cause some trouble.

Lava should not do anything to the pH. It is a volcanic rock - igneous - and is not reactive in a tank. Lava rock - either natural or man-made are wonderful platforms for beneificial bacteria because they are so porus.

Aquarium sealant will work well, but will release if you regularly bleach the rocks to clean them. Since you will need a glue with a lot of filler to it - there are no smooth even edges to join together, though, super glue and its ilk will not work.

Aquarium Sealant might actually be your best choice.

It is easy to knock off or smooth out any really sharp points on the rock, also - for it is a very soft stuff in general.....

I agree with Daryl, lave rock will have no effect on water chemistry. But for gluing the two rocks together, underwater epoxy is the perfect glue for the job. It's completely non-toxic and will even cure underwater.

Here's a link to where you can get it.

http://www.marinedepot.com/md_viewItem.asp?idproduct=TL1611

Cool! I learned something new today! I like the looks of that glue. I expect it is available in the local boat stores, also, huh?

Thank you! (Again! )

I'm sure local boat stores would have something similar, if not the exact same thing. The Aquastick epoxy works great. I've stuck all sorts of things together with it. One of my favorite applications is gluing plastic plants to a rock to get rid of those ugly green boat shaped bases.

I have to go against the grain here a bit and say that I dont think lava rock is a good coice for tankbottom substrate for goldfish. Although lava rock can easily be shaped to rounded forms, it still remains a VERY, VERY sharp substrate. Since goldfish, especially telescopes, tend to be a bit clumsy, they can and will scrape their eyes on the rocks. I have helped several members here that reported injuries from goldfish running into lava rocks in the tank.

Using lava rock is literally the equivelent to using sandpaper as a substrate. Ever see those pumice stones for exfoliating the dead skin from the bottom of your feet and callouses from your hands? Well, Pumice is actually lava rock. So, you can only imagine what lava rock will do to the soft tissues that encase the entirety of your fish. In a tank where the fish are not large or are midlevel or surface fish, lava rock is an excellent choice to decorate with. Just not for goldfish.

Lava rock is, however, a VERY good choice for use in filters as a bio-filtration media. It is in my personal favorites list for such. It just needs to be rinsed VERY well before using it. Otherwise, minute particles of the rock (its actually a kind of glass) can go through the gills or intestines fo fish and do some damage on ts way through......

The very best substrate for use in goldfish tanks is either bare-bottom, loosely scattered river rocks or gravel sized river rocks, or a layer of river rocks or gravel sized river rocks. Prefferably polished.

Just my opinion. Hope it helps.

Toothless, I completely agree with you if we were considering the lava rock as the substrate, or even as decorative rocks, in a goldfish tank. But the lava rock is going to be used in a 10 gallon tank with black neons and a honey gourami. These fish aren't nearly as prone to injury as goldfish are. In this instance, with some java ferns or moss growing on them, I think the lava rock could make a nice addition to a tropical fish tank.

I love the use of lava rock, but I also never have it in my tanks itself. I usually use them as substrate in my pond filters, and it isn't in the main filter directly. I have somewhat of a combined plant filter/bio filter after the main filter, that contains a mix of lava rocks and water plants, before the water gets returned into the pond.
Those neons and gouramis also like to nibble around in the gravel, don't they? I can only imagine what the sharp edges of lava rocks will do to the beautiful colored scales of the gourami...

Ranchugirl, Kissy isn't planning on using the lave rock as the substrate in her tropical tank. She simply though two small pieces, that fit together nicely, would make a nice mini cave in her tropical tank if they were glued together.

Thanks Bak2it

No goldfish at all, just some black neons and in the future a honey gourami and some shrimp. For substrate I have small, smooth gravel. Ouch, lava all over the place would hurt, not to mention such a harsh looking tank! In my experience, black neons never touch the gravel or anything in the tank, not even the plants. They just hover or swim around. I've heard of honey's pecking gravel like chickens on occasion looking for food leftovers on one site, but I don't think it will be a problem. I had a honey gourami in qt for a couple weeks and the first couple days she "pecked" the barebottom glass, but I think she was mainly exploring. She stopped after that, but a few days ago she got stuck to the the intake tube on my filter and died this afternoon

I'm glad you guys think its a neat and do-able idea (I think most or all would if they new the exact situation before). I think it would look very natural and give the shrimp a nice place to hide. I really thought that lava raised pH too, I guess we learn something new every day

I couldn't find that marine epoxy glue anywhere so I settled for aquarium sealant.