Adding cories to 20 gallon Platy tank

[Man with the platy fish]

Hello again everyone. I currently have 3 platies in a 20 gallon tank. The water quality is good and did a water change last weekend. So, can I add cory catfish ti my tank. I did research and sites and books say they should get along. But I don't know about the next part. Are they really happy alone? I would LIKE TO ADD 2 cories and 2 platies. Platies are hardy when it comes to water quality, but it might a little too much for the cories. What should I do? How many should I add?

 

[eaglesaquarium]

The most important question is regarding your water chemistry. What are your water parameters?


Cories generally prefer soft, acidic water. Platies are best in neutral to slightly alkaline water and with some hardness.


As far as their temperaments, they will get along fine. The issues are really with their water preferences... they aren't that similar.

 

[Man with the platy fish]

Thanks! I will work on the water. How hardy are cories? Are they super sensitive to water?

 

[eaglesaquarium]

Different species of cories have different hardiness. Some are more tolerant of harder water than others. But, that's because they come from such varied regions of the Amazonian tributaries.

They do best on sand rather than gravel as well... so that's something else to consider.


Regarding the water: Taking it to the LFS - they will test the water. You will be most interested in the 'H's. pH, GH, and KH. And please ask for the NUMBERS and UNITS for the values.

GH of 10 can be either extremely soft (if its in ppm) or hard if its German degrees of Hardness.

 

[Man with the platy fish]

Ok thanks, the Hs will help me get the tank ready for cories. My substrate isn't rough so the cories shouldn't get injured while swimming along the bottom scavenging for food.

 

[eaglesaquarium]

Its not as much about roughness. Cories actually sift sand grains through their gills searching for food. They can't do that on gravel

 

[Man with the platy fish]

Ok, but will i be over stocking if i add 2 of each?

 

[Essjay]

Cories need to be in a group of at least 6 as they are sociable shoaling fish. If you are looking at one of the dwarf species (pygmaeus, habrosus or hastatus), you'd need at least 10 of them.

But you need to know how hard your water is first. Your water provider's website may gave your hardness - look for a number and the unit not some vague words.

 

[Byron]

Agree with others. Do not rush into this, research and then decide on the issues. If you get cories, (1) they must have five or six minimum. (2) you need to know your water parameters for the tap water (GH and pH). (3) Sand is definitely preferable.

 

[Man with the platy fish]

Ok thanks everyone... I do have my own water test kit and equipment. Im not so sure about the local pet stores. I will replace the gravel with sand and put together a group of 5 to 6 cories. Any recommended sand brands?

 

[Man with the platy fish]

How many cories should i add at a time to my 20 gallon tank?

 

[Jordan_Deus]

Ok thanks everyone... I do have my own water test kit and equipment. Im not so sure about the local pet stores. I will replace the gravel with sand and put together a group of 5 to 6 cories. Any recommended sand brands?

I recommend Pool filter sand as it is inert, grains aren't too small as to form dust clouds, and in my opinion it looks good...

How many cories should i add at a time to my 20 gallon tank?

You should add all the Corydoras at the same time as to cause the fish less stress and allow them to establish a hierarchy.

 

[Man with the platy fish]

Alright! That won't affect my platies health, adding 5 at a time, right? Thanks for the recommendation!

 

[Man with the platy fish]

Here is what i have so far on cories:
Cory catfish should be kept in a tank of 72 to 78 degrees Fahrenheit with sand substrate. They should be fed sinking pellets specifically for their species, and they also scanvenge for leftover food and algae. They get to a size of 2 to 3 inches and get along with platies : ). They should also be kept with at least 5 others of their kind. Anything else i need to know?

 

[Byron]

Re the sand, do not get white as this affects fish. Dark hue sand is fine. You can buy aquarium sand which will be more expensive (make sure it is inert, calcareous sands will increase GH and pH). Or you can use play sand. Construction sands are not advisable due to sharpness, but play sand is highly refined.

And add the cories together. Any shoaling fish species that need a group are better added together at the same time. They will settle in faster, meaning less stress and risk of problems like ich. Another reason which doesn't matter for cories but would for some species is that they form an hierarchy and if more are added later this can be trouble.