# Light Artificial Rocks



## CichlidsTank (Sep 27, 2009)

Whenever I try to catch a holding female to separate her for fry release, I have to remove 30-40 small/medium rocks from my tank. If I don't remove the rocks I end up spending way to much time chasing fish around with a net.

I've tried the turn lights off/flashlight trick to catch fish, but it isn't easy with all my rocks...

...After I finally catch the fish, I have to put all the removed rocks back. It can be a pain because they are heavy and if dropped could crack the bottom of tank if not placed gently.

...So I was thinking about trying to make 2-3 large artificial rocks that are light weight. That way there would only be 3 rocks to remove/replace, and sense they are light weight I wouldn't have to worry about dropping them and cracking the bottom of the tank.

I have 3 ideas to make the rocks:
1- Great Stuff/Polyblend/Neodymium Magnets (like this: 



)
2- Paper mache structure/Polyblend/Neodynium Magnets
3- Styrofoam/Polyblend/Neodynium Magnets

The neodymium magnets would hopefully prevent the rocks from floating.

.....
Has anyone made any rock structures like this or have any suggestions on what to make the fake rocks out of?


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## The King Crabb (Jun 28, 2011)

Something to realize is that styrofoam of any make is incredibly buoyant. You're going to need those magnets to be extremely powerful to keep it submerged under that much water!


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## PfunMo (Jul 30, 2009)

I tried some DIY rocks but stopped due to the lack of natural looking rock. I would suggest trying your hand at hypertufa rock making. The mix can be varied to adjust the weight and strength of the rock. Hypertufa is a modified mix of cement and other ingredients to replace the sand and gravel normally used in concrete. By using various mixes, you can get lighter weight rocks but as you replace the sand and gravel it does usually result in a weaker mix.

I found my "rocks" looked more like ugly blobs of concrete!! Fine for flowerpots but bad for tanks.


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## pistolpete (Dec 28, 2009)

Have you tried two nets? I have had good success with one large net held between the fish and the hiding spot and a second small net to chase the fish into the big net. Somehow when the net is not moving they stop seeing it as a threat. You can even leave it in the tank for a couple of hours before launching the capture mission.

As for the rocks, I always favor natural materials. Real rocks are safer, easier, and cheaper. I set tile for a living, grout has both acrylic polymer and mildewcides mixed into it and may not be the best choice for a fish tank.


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## Sub-Mariner (Dec 7, 2011)

pistolpete said:


> Real rocks are safer, easier, and cheaper.


For the most part real rocks are cheaper but how are they safer and easier?


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## pistolpete (Dec 28, 2009)

Artificial rocks are made with a variety of resins and pigments. In a closed system like a fish tank you can get accumulation of toxins pretty quickly. Sure the manufacturers claim it's all safe and everything, but they don't have to test anything because it's not for human consumption. That's why I'd say real rocks are safer.

As far as easier: I've always found it pretty quick to go to an abandoned gravel pit somewhere, pisk up a few buckets of rocks. A quick wash and they're good to go. Compared to trying to glue foam to the back of a tank I'd say it's easier.

The OP has a point, if he's regularly having to move things around, but I rarely touch my rocks more than once a year.


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## jmlp3 (Jan 9, 2011)

Why not try pumice stone. It can be found at your local landscaping store. Its light weight, and porous, and buoyant, the trick to get them to sink is to boil first then immediately immerse in a bucket of cold water, and that will fill the pores to allow the stone to sink.

Really cool actually, my tank is full of them, you can hollow out with a drill and make caves, etc, and it is a great surface to aid in benefial bacteria, plus green algae.

Just my thoughts, hope that it helps.


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## CichlidsTank (Sep 27, 2009)

jmlp3 said:


> Why not try pumice stone.


Is that rock too rough for fish to be swimming in and out off. Will it damage fins?


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## jmlp3 (Jan 9, 2011)

I have them in my tank for over a year and a half. I have never really seen them hurt themselves on the rock, the only mishaps I see happening is agression and that is the only harm I see. The fish will not intentionally go into the rocks to harm themselves, it is usually agression problems that may cause injury.

I have a good layer of algae growth on them as well, which provides a good cushion.

But yeah, you are right, they can be sharp, and you must handle with care otherwise you will cut your fingers.


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## CichlidsTank (Sep 27, 2009)

It sound like they'd be ok. My fish occasionly bang against rocks to adjust eggs/fry in their mouth or adjust food, or just for fun. But is another option I have to think about.


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## crabbejoe (Aug 3, 2006)

I've had good success with taking natural rocks and covering them with black waterfall foam. It should be at least 2/3 rock, 1/3 foam to get them to sink. They turn out kind of glossy looking at first, but over time look like real rocks. Also if you aren't patient enough to wait for the gloss to fade, you can shave the outer edge off with a knife and it looks like porous black lava rock underneath. The foam is supposed to be fish safe, intended for koi ponds. I haven't had any problems in the year or more I've had them in my tank.


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## crabbejoe (Aug 3, 2006)

Here's an example of one. It's in a saltwater tank. Real rocks on the left and right of it.


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