Fish in my 20 gallon

[portia]

There is quite a bit of conflicting information out there on compatible fish, fish for the newbie, etc.

Right now, I have a 20 gal tank that's about 1 1/2 months old. I've had a swordtail and a platy for several weeks. Doing fine, eating like pigs, good color, swim around actively. Last weekend, I added an oto cat (very small) and a dwarf gourami. The oto hides but when I see him, he looks ok. The dwarf gourami has beautiful color, also eats like a pig and is very active.

But when I was researching what to add in my next round, I looked at the requiurements for these fish and they seem to be somewhat incompatible, yet they're all doing fine.

What the heck is KH? Because the fish I have have quite different ones. It says 4-10 for the gourami and 12-30 for the sword and 10-25 for the platy. Yet whatever mine is (which I don't know b/c I don't know what KH means), the fish are all thriving.

Do I really need to get a couple more otos? Some sites say they need buddies, but then they say they don't have a good record of living and I don't want to waste my money. Also, if they're all going to hide all the time, I don't want to waste tank space on fish I never see.


Thanks in advance for any help.

 

[thominil]

How much algae do you have in your tank, because that tends to be the main source of food for oto's. Yes, they should be in groups.

 

[portia]

I don't know. it's not that visible.

He spends his time scruffing around under the rocks. He did pop out this morning when I was feeding them, grab a piece of flake food, and pop back under the rock.

What about the rest of my question? If I get him buddies, will he be less shy, or are they all going to hide under the rocks together? Because that isn't very satisfying for a new fish owner.

 

[thominil]

Here's a few links on them:

Otocinclus affinis, with care, maintenance requirements and breeding information for your tropical fish
http://www.fishpondinfo.com/otto.htm

 

[thominil]

He should be less shy, get like 2-3 more.

 

[portia]

Thanks to Thominil.

What about the KH thing? Anybody?

 

[thominil]

Answered wrong. My bad.

 

[JustOneMore20]

KH is carbonate hardness. I wouldn't worry much about that when it comes to the needs of the fish you have now. If the fish are thriving and eating well, its probably fine. It comes into play more so in planted tanks and when your trying to breed certain fish.

 

[bs6749]

As mentioned, KH is called carbonate hardness, and it is a measure of the buffering capacity of the tank. The buffering capacity is how well the tank will resist changes in pH. If you have pure water for instance with a pH of 7.0, a GH of 0 ppm, and a KH of 0 ppm, than adding a drop of a strong acid, such as hydrochloric acid, will significantly alter the pH of the water depending on the volume of water it was added to. pH swings can be deadly to fish, generally the swings are more deadly when you go from an acidic water to an alkaline water. The reason for this has to do with the equilibrium of the ammonia molecule (NH3) and ammonium ion (NH4+). Under acidic conditions, the toxic ammonia molecule is readily converted to the far less harmful ammonium ion due to there being free hydronium ions in the water to bond to the ammonia molecule. This molecule is stable in acidic conditions, but in alkaline conditions where hydroxyl ions (-OH) are present, the positively charged ammonium ion wants to give up a hydrogen and it does so readily, becoming the toxic ammonia molecule. Having a high KH ensures that pH swings such as these don't happen and the fish don't suffer. There is something called "old tank syndrome" where an established aquarium's water goes to the acidic side (naturally) after decay of food, live plants, dead fish that are unremoved, etc. Basically the tank is neglected and ammonia is produced in greater amounts than the beneficial bacteria can handle, all from decaying matter. Since the pH is acidic, these harmful molecules are converted to the less harmful ammonium ion. Now the hobbyist decides to do a large water change since they haven't done one in nearly a year. The fresh water added to the tank is most likely either neutral or alkaline. In either case it shifts the equilibrium to the formation of toxic ammonia molecules and most of the fish die in a couple of days and they hobbyist is left wondering why. Because they just added fresh water to the tank, and they don't think that would hurt the fish, but in all reality that along with several months of neglect killed the fish.

So yeah, make sure you have sufficient KH and you will avoid pH swings like that which can kill your fish. pH swings themselves aren't that bad for the fish it's what forms in the water as a result of those swings that can be deadly to the fish.