15 Gal Stocking Idea

[Adohan]

Hey,
 
Currently have a 15 Gallon Square planted tank with a 7.4ph containing a 1 male guppy, 4 Glowlight Halquins and 2 Amano Shrimp.  I am looking for ideas for the last 25cm of fish.  currently the top half of my tank has losts of active with most of the fish swiming in that area.  So mainly looking for something that would ocuppy the mid-bottom half and that will school to gether nicly. 
 
Currently I am thinking of maybe a group of one of the following tetras:
Rummy nose tetra (heared they do not handle ph changes or above 7 very well)
Neon tetra (heared they do not school very well and kind do there own thing unless they are stressed)
Red Phantom tetras
 
Can you give any advice or better alternative small fish that school well in the bottom half of the tank.
 

 

[Far_King]

If you were to add any more fish ideally you'd increase the numbers of Harlequins or add more male guppies.   I'd avoid female guppies as you'll be over-run in no time.  Snakeskin guppies are among the most attractive fish you can buy in my opinion.
A decent shoal of Harlequins likewise can look absolutely spectacular.
 
You are correct, RummyNose are not suited to your tank due to the pH, they prefer more acidic water around pH6.

 

[Adohan]

I was planning the add more Harlequins, the thing is I want another group of fish that would stay in the bottom half of the tank, as the Harlequins only seem to swim above the mid line of the tank.
 
Ideally
Top half: 4-8 Harlequins(depending on tetra size)
Bottom half: 4-6 Small tetras
 
Can you give any advice or better alternative small fish that school well in the bottom half of the tank.?

 

[Byron]

This is a very small space, and small water volume (the two are not always the same with respect to the fish needs).  As this is a "square" rather than a longer tank, active swimming fish (as the rummys would be) are not the best choice, regardless of the parameter issue.  Your existing stock is better suited to this type of tank, as they are not "distance swimming" fish, if that is understandable.  By Glowlight Harlequin, I am assuming this is the species Trigonostigma hengeli.
 
With the volume in mind, I would not add another upper fish, by which I mean anything above the substrate.  I would suggest a substrate-level fish, such as a small group of corys.  These would provide interest as they can be somewhat active, but they will remain close or on the substrate for the most part.  A group of five or six of one of the medium-sized species should work, and manage in your parameters.  Though the GH (hardness) is not mentioned, and this is more important for fish than the pH provided the latter is not extreme, but I will assume the GH is in the moderate range with a pH in the low 7's.
 
So, up the rasboras to at least seven, or eight in total; this species does better with a few more so this will improve their well being as well as add more fish.  I would not add more guppies (thinking of water volume here).  And then select a species of medium-sized cory that will suit your water and the "quiet" nature.  One cory often looked at is the panda, Corydoras panda, but this is not the species that I would consider here, assuming your water flow from the filter is gentle as the rasbora prefer.  C. panda like currents, something the rasbora do not appreciate.  The pepper cory, Corydoras paleatus, should work, in a group of 5-6.  Corydoras sterbai is another.  Both of these are now commercially raised, as opposed to wild caught, so unless your GH is very high they should be fine.
 
Byron.

 

[Adohan]

Have not measured my hardness value but according to my water company it was 15 Degree Clarks last time measured, do not know what that is in GH.
 
Was looking at bottom fish and saw Oto cats, would you recomemd some of those with or instead of the corys.
 
I have herd that cory mess/dig up plants quite alot.

 

[Byron]

Have not measured my hardness value but according to my water company it was 15 Degree Clarks last time measured, do not know what that is in GH.
 
Was looking at bottom fish and saw Oto cats, would you recomemd some of those with or instead of the corys.
 
I have herd that cory mess/dig up plants quite alot.

 
The GH at 15 d Clark equates to 214 mg/l or ppm (these two are the same), which is roughly 12 dGH.  I would call this moderately hard.  Not really anything to worry about here.  The GH of the tap water is not going to change much, if at all, in the aquarium, unless you specifically target it.  For example, if you used a calcareous substrate (crushed coral, limestone, marble, shell, dolomite, aragonite) this would slowly release mineral (calcium and/or magnesium) and harden the water.  But otherwise, no.
 
Otocinclus are not really "substrate" fish.  They spend all their time on surfaces, primarily plant leaves, but also wood, grazing algae from the biofilm.  They might hit the substrate now and then, or to feed off sinking food tabs, etc, but otherwise they are up and usually unseen.  They are also highly sensitive to water quality and parameters, being wild caught.  Corys are much better as interesting fish as they are mainly out and about.
 
I have never had corys dig up plants.  But all my substrate-rooted plants are substantial (swords, chain swords, crypts, aponogeton, tiger lotus).  I suppose the delicate plants like baby tears and similar "carpet" plants might be a problem at least until they are established.  Not something I would worry about.
 
Byron.

 

[Adohan]

Thanks, will look out for some Dwarf/Pigym Cory when I next go to my fish store.

 

[Adohan]

I have never had corys dig up plants.  But all my substrate-rooted plants are substantial (swords, chain swords, crypts, aponogeton, tiger lotus).  I suppose the delicate plants like baby tears and similar "carpet" plants might be a problem at least until they are established.  Not something I would worry about.
 

 
The book I have from when I set up my aquarium, recomemdes not having Echinodorus based plants in with catfish.
I have two types in my aquarium but you applied that yours are fine.  Has anyone had problems?

 

[Byron]

Thanks, will look out for some Dwarf/Pigym Cory when I next go to my fish store.
 

 
Here we have some issues.  The "dwarf" species of cory are very sensitive.  For one thing, they must have a sand substrate.  Sand is best for all corys, but these little ones absolutely must have it for their well-being.  They seem particularly affected by water parameters. I would stay with some of the larger but still medium-sized species like I previously mentioned.  
 

The book I have from when I set up my aquarium, recomemdes not having Echinodorus based plants in with catfish.
I have two types in my aquarium but you applied that yours are fine.  Has anyone had problems?
 

 
"Catfish" is a very broad term.  I have had Echinodorus species of swords for 20 years, and I have always had Corydoras cats in these tanks.  Even the two chain species that are now in Helanthium have thrived and spread like weeds with corys present.
 
I have had Hypostomus plecs dig up plants, in their personal re-arranging of the sand, and I can image other types of catfish doing this.  Loaches can too.