Setting up natural cory habitat tank from scratch -- advice?

[LughLamfada, posts: 15]

Hello everyone,

I'm new here, but I've been lurking on this site for quite some time. I am looking to break down my current 20-gallon long tank (30x12x12) and replace it with a 37-gallon (30x12x22). The smaller tank is currently occupied by a breeding shoal of peppered cories, a few pitbull plecos, and another small shoal of habrosus cories. I have had the smaller tank set up for about five years and want to treat the fish to a new tank that more closely resembles their natural habitat. Here's what I'm thinking:

-sand substrate mixed with assorted smooth pebbles of differing sizes
-driftwood roots that occupy most of the lower part of the tank near the substrate
-amazon plants that would be found in the various rivers they inhabit (and that aren't susceptible to black beard/bush algae)
-an external canister filter (suggestions welcome, currently have an AquaClear 70 hob)

The only real concern I have is what type of sand to use. In the past, I attempted to use playsand at a thickness of about 1.5 inches but found that it quickly went anaerobic. I want to have sand that the fish will enjoy but that won't go supremely toxic on them in a matter of a few days, so I'm open to suggestions. I live in Florida so I have plentiful access to beach sand (mostly silica and tiny crushed, smooth shells) but am unsure if its suitable for the catfish or for some of the plants I intend to have in the tank. Your suggestions are greatly appreciated.

-Lugh

[sidguppy, posts: 3827]

watch the movies!











these should give you plenty inspiration on how to build a natural looking Corydoras biotope.

[RickE, posts: 438]

It's probably worth mentioning that the beach sand will almost certainly not be suitable for this project but the play sand should be fine. You only need ~ 1/2 inch then it will get turned over and won't go anaerobic.

[dw1305, posts: 332]

Hi all,
You can use a slightly thicker sand layer if you have Amazon Swords or Cryptocoryne spp. (from SE Asia, but suitable otherwise), these have a very extensive root system in sand and will keep the substrate aerobic. As well as a some broad leaved plants I'd have some with fine leaves, Cabomba caroliniana would do, and you could also try Heteranthera zosterifolia.

BBA will grow on all types of permanent hard substrate (including long-lived leaves), if you want to limit you need to restrict the light with some floating plants, any of Salvinia, Pistia or Limnobium would be suitably S. American.

Finally I'd definitely add some dead leaves, they are biotope appropriate for a lot of habitats, and they provide grazing surfaces for smaller Corydoras spp. and fry.

Have a look a this thread: <http://www.planetcatfish.com/forum/viewtopic.php?f=6&t=35069>.

cheers Darrel

[Shane]

The only real concern I have is what type of sand to use. In the past, I attempted to use playsand at a thickness of about 1.5 inches but found that it quickly went anaerobic.

I am using playsand myself (purchased from Toys R Us) in several tanks and am happy with it. That said, the deepest I have it in a tank is maybe 1/2 inch. Several of my fellow local club members use pool filter sand and swear by it. It is available at any pool supply store.
If you want a deep enough substrate for plants, I think you will be far better off laying down a substrate of one of the potting aquarium gravels (like Azoo, Caribsea, Fluval, etc), planting the tank, and then going back and adding a 1/2 inch layer of the sand/gravel mix you want to create. Alternatively, if you do not wish to plant the entire tank, you can create raised planting beds in one or more areas with stones or driftwood. You could then plant these areas and cover the remaining substrate area with a thin layer of sand/gravel.
-Shane

[MChambers, posts: 70]

I'm one of Shane's fellow club hobbyists who swears by pool filter sand. It's coarser and heavier than play sand, which makes it easier to clean and maintain. My corydoras thrive in it, but it may not be as typical of their natural environment as play sand. (I've never been to South America.)

[Mike_Noren, posts: 1395]

It's not a problem if the sand goes anaerobic - in fact it's natural and harmless. The worst it can do is make the water smell like fart, and if that happens you've been neglecting your tank very badly indeed.

[MatsP]

It's not a problem if the sand goes anaerobic - in fact it's natural and harmless.

As long as no large deposits of Hydrogen Sulphide is suddenly released - or is that another myth?

--
Mats

[LughLamfada, posts: 15]

Thank you everyone for the great replies. As you can see, I'm rather attached to my shoal-- they've rolled their eyes all the way into my heart, you could say.

Anyhow, I had been considering going with a layer of potting gravel for the plants followed by a layer of sand but again, I was concerned about hydrogen sulfide. I'm married to a chemistry PhD who was telling me all of the adverse effects of H2S exposure during my first experiment with play sand which in turn led to me replacing it with smooth gravel.

I think I might go with the pool filter sand since it seems that it isn't as susceptible to getting packed solid as I've seen happen with play sand. I'm currently using an AquaClear 70 hob filter but am thinking about a Fluval or Eheim canister filter. What do you all prefer?

[jvision, posts: 128]

Malaysian Trumpet Snails are awesome for keeping deeper sand beds turned, and preventing anaerobic conditions. I've been keeping planted tanks with sand beds that are sometimes 4-5" deep, and the MTS are what I use to keep things fresh in the substrate.

[jp11biod, posts: 131]

I just installed my first canister ever on a 110 gal, a Fluval 406, and have been incredibly impressed with it since. It goes together easily, engineered smartly, quiet, and did not leak one drop of water throughout my clumsy install.

Awesome first impression.

[MChambers, posts: 70]

I love my Eheim canisters. Never tried a Fluval; it's possible I'd be just as happy with them.

[LughLamfada, posts: 15]

I know that cories prefer water that has a very low flow rate, almost stagnant. Would a canister be overkill? And what are folks' thoughts on lighting? Right now I have a standard fluorescent tube light but have been thinking about the dynamic lighting solutions or an LED.

[MChambers, posts: 70]

I know that cories prefer water that has a very low flow rate, almost stagnant. Would a canister be overkill? And what are folks' thoughts on lighting? Right now I have a standard fluorescent tube light but have been thinking about the dynamic lighting solutions or an LED.

Depends on the canister. Eheims tend to have lower flow rates than other brands, which leads many folks to "overfilter" -- buy a bigger canister than recommended by Eheim for a particular sized tank. I have an Eheim 2211 on a 20 long tank and 2 2213s on 29 tanks and they're fine.

LEDs aren't very good for growing plants, except low light plants. They are pretty, however, and don't use much electricity.

[Mike_Noren, posts: 1395]

I know that cories prefer water that has a very low flow rate, almost stagnant.

Pretty sure that very much depends on species, e.g. these are in stronger current than you'll ever be able to create in your aquarium.
Also remember that all the videos are shot during the dry season when flow is at its lowest.

[RickE, posts: 438]

Very interesting that Mike. Nice sandy bottom like we all recommend too

[Mike_Noren, posts: 1395]

Very interesting that Mike. Nice sandy bottom like we all recommend too

No fish have read the books.
Here's another group living in fairly flowing water, although this time the bottom is indeed sand.

[LughLamfada, posts: 15]

And any thoughts on a C02 system? Is it necessary?

[Mike_Noren, posts: 1395]

As long as no large deposits of Hydrogen Sulphide is suddenly released - or is that another myth?

Yes, it's largely a myth. All natural sediments are anoxic, typically the oxic layer is just millimeters to at most a few centimeters thick - yet fish do just fine, because hydrogen sulphide isn't particularly mobile, isn't particularly toxic, and if released into an oxic environment rapidly oxidized. Not to mention that a fish like Corydoras, which in nature spends much of its time head-down in sediment, is guaranteed to be adapted to handle hydrogen sulphide.
Hydrogen sulphide is a hazard if you have enormous amounts of it and rapidly release it, a situation you're unlikely to manage to create in an aquarium.

[Shane]

No fish have read the books.

True, and the genus did not evolve into 100s of different species by inhabiting only one environment. There are corys that live in fast moving piedmont streams over stones (see some of the habitat pics for Corydoras venezuelanus for example), those found over leaf litter, and those that prefer sand. One can always shoot to duplicate the exact habitat of a certain species or go for a more general suitable captive environment.
For most corys a sand substrate and gentle current is a suitable captive habitat, but it may not reflect their actual natural habitat remotely. The only time I have seen corys in near stagnant conditions was at the height of the dry season, and those conditions only last a few months of the year.
-Shane