Can I put fresh water fish in a tank with crushed coral and tufa rock?

Question

I just purchased an Eclipse Hex 5. Thirteen years ago I had a beautiful 75 gallon saltwater tank that failed miserably. Long story short, all I have now is the crushed coral, tufa, and barnacles. They were quite expensive, and I have a bunch, so they are getting used. Plus, I really like how they look.

Anyway, I bought this new aquarium to amuse my cat, which in turn amuses me.

The girl at the pet store said I would be fine, but I seem to remember being cautioned about this. I don't want to kill a fish in the process, so any help is appreciated.

I don't mind going saltwater, so if you have any advice on this tank and saltwater fish, please respond.

I understand the tank size thing, and fish types. I'll probably put just a couple of small non-aggressive fish or a tang in it. The lack of airation concerns me. I know the Bio Wheel is supposed to replace that, but does it work?

Thanks

Answer 1

The reason you were cautioned about using the materials for freshwater is that in water with a pH below 7.8 (most tapwater), these materials tend to dissolve slowly, increasing both the pH and hardness of your water. Not may fish appreciate their conditions fluctuating with every water changem which it would under these conditions.

The material is fine for use with cichlids requiring higher pH (mostly Africans), or other fish that require brackish conditions. The problem here is most of the species that need these conditions will grow too large to keep in a 5 gallon tank (especially a hex, since it's taller than wide, and most fish don't swim vertically).

One possibility is to use a few guppies or platys (all males so they won't reproduce). These fish tend to do better in higher water hardness, so they won't mind the substrate. If you wanted to do something really different, are you aware that guppies can be converted to full saltwater if acclimated slowly (over a period of a week or so). I currently have I trio of guppies that spawn regularly in saltwater - and unlike most people who have guppy fry, my LFS is happy to take mine to sell to people who are looking for small saltwater fish to use for cycling nano reef tanks. It makes quite a conversation starter when you have someone see a tank with guppies swimming around with live corals.

As far as saltwater species, there really isn't much suitable for a 5 gallon other than possibly one clown goby or very small shrimp goby, and these really should have a 10 gallon at least. A tang will get too large for any tank smaller than a 55. And with such a small size, you'll have trouble keeping the temperature and water chemistry (especially salinity) constant.

The amount of dissolved oxygen in the water is a function of water movement at the surface. If you used an airstone previously, a filter will give you more O2 in the water with better circulation than the airstone did. The movement of bubbles is upward and they burst so quickly that the bubbles themselves do little to increase the amount of dissolved O2. It's only because the bubbles spread out before they burst, and the water being pulled up through the tubes (if an undergravel filter was used) in turn caused the oxygenated water to move down to replace it that the air pump does any oxygenating at all. The power of the filter is much greater in terms of the total amount of surface area disturbed, and the ability to circulate the oxygenated water at the top throughout the tank.

Answer 2

Florida Crushed Coral

Answer 3

Well the reason you are concerned about the crushed coral and tufa rock and barnacles is because these items raise the PH in a tank therefore making it a bad mix with most freshwater fish as most prefer a lower pH and softer water. There is one kind of freshwater fish that thrive in high pH and hard alkaline water and that is any African cichlid. These items are ideal for these fish as they will raise the pH naturally due to all of the calcium and magnesium in this decor that slowly disolves overtime increasing the kH (carbonate harness) which in turn increases the pH.

African cichlids thrive in a pH of around 8.2 or higher which is much higher than most other tropical freshwater fish. Unfortunately a 5 gal is far too small to keep any African cichid in so I am afraid you are out of luck there and since I really don't know much about saltwater fish I cannot make a suggestion but I have come to understand that it is more difficult to keep the water parameters stable in a small saltwater or "nano" tank where it is much easier to have success in saltwater in a larger tank. I know there are some fancy saltwater shrimp that may be suitable for that size but again the water parameter stability could be a problem.

I also have a 5gal hex that eternaly amuses my dog who loves to lay on the couch and watch the tank. I keep fancy guppies in mine and I find that this has worked out very well as guppies are not demanding on having large tanks to be happy. Of course you would not be able to use the crushed coral, tufa, or barnacles with fish such as guppies or most other tropicals as I had mentioned so depending on what someone with more saltwater experience may suggest, I might consider getting rid of the tufa etc. and go with easy freshwater fish like guppies or a betta or platies IMO.

I hope this info may have been helpful. If you are interested in learning more about the effects of tank decor on the water chemistry you may want to read this article that I wrote on the topic as this is something I have been studying and have had interest in based on the observations of two of my own tanks with opposite parameters due to the choices in aquarium decor. Good luck with you new tank.

http://www.fishlesscycling.com/articles/the_chemistry_of_tank_decor.html

Oh and as far as the biowheel is concerned, yes it will provide sufficient airation but you may want to add an airstone with a pump for some bubbles and additional airation if you feel inclined.

EDIT: Dam* Copperhead you are too fast for me yet again! I need to type faster!

EDIT: I had said that you may not use the coral, barnacles, and tufa with guppies but due to Copperhead's answer and experience it is perhaps quite possible. I have never kept guppies in such hard water as the water would become with these elements and I was not aware that this is possible with guppies but it makes sense since they are very adaptable fish and prefer some salt in the tank anyways. I have come to learn from Copperhead that it is even possible to acclimate them to a full salt water tank which is very interesting and is something I have not previously heard of doing. Copperhead is by far a superior and is more experienced than myself so I would certainly take his word for it. Perhaps guppies would really be your best bet with the coral etc. whether freshwater or saltwater, but again the freshwater will be alot easier to maintain than saltwater for that size of tank and is probably better for the guppies to be in harder alkaline water than in full saltwater IMO.

Answer 4

Generally speaking, one should not put seashells or coral into a freshwater tank. They are composed of calcium carbonate which will dissolve and increase the PH of the water. Save coral/shells for your saltwater tank.