Newcomer Question

[JoeSmith]

I am new to this forum and new to owning fish other than my betta fish.  Several weeks ago I purchased a 20 gallon tank which now has plenty of live plants and a few rock decorations.  Currently I have one guppy, 5 black skirt tetras, and one dwarf orange crayfish.  All the current residents seem very happy and healthy.  I would like to add 5 cory catfish but I'm not sure if I will be setting myself up to overstock my tank once all of these fish are full grown.  I'm also unsure if all these fish residents will get along OK.  Maybe a smaller species of the corys would work.  Does anyone have any suggestions?

 

[Munroco]

No experience at all of crayfish, would be concerned that cories being bottom dwellers would become its prey. Welcome to forums BTW
 
Having read up about the crayfish since my reply, it looks like they are fairly small and peaceful and don't have the big claws I was expecting. Adding 5 cories wouldn't be overstocking IMO. What are your water parameters?

 

[JoeSmith]

I've had fish in my tank a little more than 3 weeks now and have been adding API quick start here and there with plenty of plants.  Been doing about 20% water changes every 3 or 4 days while im early into setting it up.  My ammonia has finally gotten to 0 ppm, it was hovering .25 for a while, nitrite is 0 nitrate is 5.  PH in the tank is 7.5.  Will adding all 5 corys at once significantly throw off these levels?  And would they be happy with just 5 of them?
 
And yes so far the crayfish has not bothered any fish just crawls around on the plants.
 
Thanks!

 

[Akasha72]

5 cories is the recommended number but they must all be the same species of cory ... for instance 5 bronze cory, or 5 panda cory ... you can not have say one bronze, one panda, one peppered etc. The reason for this is that cories are a shoaling species which live in large groups in the wild and so we recommend keeping them in a group of 5 or 6 of each variety... does that make sense?

 

[Ch4rlie]

Before going any further with which cories you'd think suitable for your tank, you must find out your water hardness, your local water supplier online should have all the information on water hardness for your area.

This is due to the fact cories are softer water species. Means they do not do well in hard water.

 

[Akasha72]

agreed

 

[JoeSmith]

Will the KH and GH values give me a good idea of what my water hardness is?  Im having a hard time finding and interpreting mine online.

 

[Ch4rlie]

Yes, kH and gH would be most helpful as well as the pH which you can do from own test kit easily enough.

These online water supply info can be confusing and can have different scales of measurements.

In general you should find these values under water hardness but not always as simple as that.

Alternatively you can take a screenshot/s and post them here, we may be able to help decipher that.

 

[JoeSmith]

GH appears to be 30 and KH appears to be 40.  Ph has been consistantly reading at 7.4.  Would that be acceptable for some small corys?

 

[Ch4rlie]

Just to be sure, what unit of measurement are these figures under?

 

[JoeSmith]

Right that might help

 .  Both are in ppm or mg/L.

 

[Ch4rlie]

Right, 30 ppm is about 1.8 dGH and 40 ppm is around 2.4 dGH
 
This is soft water.
 
Good for most cories, might be a little on the soft side for some but should be ok. Do research whihc cories you'd like just to be certain they will thrive in your tank water.
 
Note, cories do best in groups, imho of at least 8+, most folks will say 6+. But the more, the better
 
 
And one last note, your guppy will not really appreciate soft water. They are a hard water specie.

 

[JoeSmith]

The only reason I was against getting more than say 6 was I was afraid to overload my tank.  I guess I'll see how large they get maybe I can consider getting a few more.
 
 Thanks for the help from everyone!  I'm sure I'll have another question in the future.

 

[Akasha72]

if you like cories have you had a look on planet catfish? That's a really good place to research the very many types of corydora ... some stay relitively small others get quite big .. it's always best to know this info before buying

 

[JoeSmith]

Thank you everyone.  I ended up getting a small school of 6 Julii Corys.  Perhaps they are false Julii's but I cant really tell them apart.  They seem to enjoy their new home.  The dwarf crayfish doesn't seem to bother them, just raises his claws when they get to close and the cory quickly flees.
 
Also, Ch4rlie, I think you are right, my guppy seems stressed out.  Will sometimes swim up and down the tank wall over and over.  My friend keeps several guppies.  All seem to be happy and says he will take him off my hands.