“Is this safe” thread.

[AKfish]

Hello. I do know that sand can scratch some fish up a bit. The courser the worse obviously. But sand is essentially ground glass chunks. Most sand under a microscope looks very jagged. Smaller bottom dwelling fish can be and I emphasis CAN be effected by this. I live in Alaska and use glacial sand. As the name suggests if was formed by glaciers and is actually rounded under magnification.

 

[PheonixKingZ]

That is why I am kind of reluctant to get Cory cats.

But don’t Cory cats “need” sand?

 

[Byron]

First, sand is not ground glass chunks. Sand is the granular material composed of rocks that have been worn down over time by nature (as in the sand in the rivers, lakes and oceans) or been ground down mechanically as in commercial sands. There may or may not be ground glass sand but is should not be used in an aquarium if it does exist.

Aquarium sand, that is specifically made for use in an aquarium, is composed of ground rock. So is play sand, and most industrial sands though aside from play sand some of the industrial sands can be rough. Play sand is the most refined of the industrial-type sands and it is completely safe in an aquarium. It is "play sand" because it is used in children's sand boxes and everyone knows it can get into their eyes and mouth. It is safe, period.

Cories must have sand. They live over substrates of either sand or mud or both, and they filter this through their gills while looking for food. Play sand is the safest sand. Aquarium sands should be, if they are just inert sand and not some plant-specific substrate as these can be very rough for fish.

 

[PheonixKingZ]

But a 10 gal. Tank is to small for cory cats, right?

 

[Byron]

But a 10 gal. Tank is to small for cory cats, right?

The "dwarf" species Corydoras pygmaeus, C. habrosus and C. hastatus would be fine in a group of 10-12 in a 10g tank. The larger sized species I would recommend for larger tanks.

 

[PheonixKingZ]

You mean 10-12 Pygm Cory cats in a 10 gal. Only?

 

[Byron]

You mean 10-12 Pygm Cory cats in a 10 gal. Only?

No, not necessarily. I had a 10g running a few years back that had 10 pygmy cories, 12 Boraras brigittae, live plants, snails. No filter. Just a heater. I moved the 10g and added a sponge filter and removed the Boraras to another tank, and kept the 10g for my pygmy cories. They spawn regularly, and some fry survive because there are no predators and they find sufficient live foods like infusoria. I let nature take its course, and I didn't want all these fish anyway so not all of the fry survive, just the odd one. I've lost all the originals by now, it has been 8 years I think, so the existing group of I'm not sure how many are all fry and fry of fry, etc.

 

[PheonixKingZ]

No filter? Do theses tank actually work? I would think that a ton of bio-film would form on the surface of the water.

So would 10-12 Pygmy Cory cats, and Boraras (I have never heard of these.) work in a 10 gal. Tank?

 

[Byron]

So would 10-12 Pygmy Cory cats, and Boraras (I have never heard of these.) work in a 10 gal. Tank?

Yes, I said that in post #22. Boraras is the SE Asian fish genus of several "dwarf rasbora" species. These are "nano" fish, which is the general designation the hobby applies to very small fish that are thus usually suited to smaller tanks. They need floating plants, as do the cories for that matter.

No filter? Do theses tank actually work? I would think that a ton of bio-film would form on the surface of the water.

Any fish tank that is biologically balanced should be able to operate without any filter. Now, I would not suggest that in most cases, and I have filters on all of my tanks in my fish room, but most in this hobby have no actual understanding of what the filter actually does.

 

[PheonixKingZ]

So no other tank mates for the 2 “nano” species in the 10 gal?

 

[PheonixKingZ]

Also, for 1 tiny fish, they seem super expensive! ( $3.99 for @ fish!)

Are they also know as “Pygmy Rasbora”?

 

[seangee]

If you are looking for nano ideas you could consider CPD (celestial pearl danio).
I have a round 2 dozen in a 15G with a now untold number of red cherry shrimp.

I opted for a large group of a single species rather than more smaller groups and I am really glad I did.

 

[PheonixKingZ]

Really? So how many could I put in a 10 gal.?

(Not Just them, maybe 8-10 Pygmy Cory’s? Or would that be an overstock?)

 

[PheonixKingZ]

Do you have a filter in that tank? (The 15 gal.)

Also, what kind of substrate do you have?

 

[seangee]

Do you have a filter in that tank? (The 15 gal.)

Also, what kind of substrate do you have?

I just have a block of sponge in the filter chamber with a small pump to pull the water through it and create a fairly low flow. Tank is a Fluval flex. I replaced the stock pump (600 litres per hour iirc) with a smaller and quieter 300 litre per hour unit and then turned it down to minimum.
Substrate is "black" limpopo sand, which as you can see is not black at all

I would not get less than 10 - 15. They are quite timid so need to be in a big group and well planted tank. AFAIK they would be fine with Corys but I chose to just have shrimp in there (and a nerite, and malaysian trumpet snails, which you never see anyway).