I Thought Fish Keeping Was Simple. The Joke Is In Me.

[ShortAndSweet]

I thought it was as simple as 'set it and forget it' side from water changes and feeding. Bwahaha. Experience is a good teacher, though, and thankfully we haven't lost any fish due to negligence (we did lose two cardinal tetras a few days after purchase).

We recently had an issue with ich which was treated. Now we we have two guppies with fin rot: one in particular has a bad case of constipation even after feeding peas. Our tank parameters are good so I can only speculate that the ich make them weak so I'm off to the pet store for medication.

This is all a bit more than I bargained for but we enjoy them so much. Eventually, I'm sure, I'll end up with a small pet store in my home with all the products I'm accumulating.

 

[ShortAndSweet]

Here's the little guy in question.

 

[NickAu]

 
I thought it was as simple as 'set it and forget it' side from water changes and feeding.

It is once the tank is up and running.
 

 
Now we we have two guppies with fin rot

Fin Rot is due to poor water conditions.
 

 
Our tank parameters are good

Any chance of answering these questions please it may give us a better idea as to what is going on.
 
 
Tank size:
pH:
ammonia:
nitrite:
nitrate:
kH:
gH:
tank temp:

Fish Symptoms (include full description including lesion, color, location, fish behavior):

Volume and Frequency of water changes:

Chemical Additives or Media in your tank:

Tank inhabitants:

Recent additions to your tank (living or decoration):

Exposure to chemicals:

 

[ShortAndSweet]

Tank size: 35 gal
pH: 7.8
ammonia: 0
nitrite: 20ppm
nitrate: 0
kH: 120
gH: 150
Temp - 78

Sand substrate

Water changes/vacuumed weekly

6 guppies
6 black skirt tetras
2 Otocinclus
2 recently introduced powder blue dwarf gourami (came with ick)
2 recently introduced guppies

We have wood and rocks in the tank along with guppy grass, java fern and two other plants I've forgotten the names of.

The tank parameters changed while treating for ick. Everything looked great a few days after treatment. Then this guppy went downhill. Everyone else is acting normally and look happy.

 

[NickAu]

Hi again.
 
How much water do you change?

 

nitrite: 20ppm

In my opinion anything over zero ppm is a bad  for any fish...
 
As I do not know anything about guppies I will let others diagnose your guppie, The reason I asked the above questions was to save time in diagnosing. Its easier with that info at hand.
 
I love guppies I have never had any luck keeping them.

 

[stanleo]

Your tank is still cycling. Since you already have fish you will have to do regular water changes to keep the nitrite level as low as possible. I would do a 25% water change every 2 days depending on daily water tests. Once the nitrite is at 0 you can hold off on the water changes until you see nitrates rise. Then your tank will be cycled. Nitrite is poisonous to all fish. Some can tolerate it for longer periods and at higher concentrations than others but it will eventually kill them all. 
 
This is assuming you haven't made the most common beginner mistake and confused nitrites and nitrates. If you haven't confused them I guarantee that the nitrites being 20ppm is your problem. 
 
Once you get the tank cycled all you need to do is weekly 20% water changes, feed them and it is very simple indeed. You don't even have to clean the filters unless the flow slows significantly. 

 

[ShortAndSweet]

It was 20ppm just before water change. It's been set up for over 6 months and has certainly cycled.

I do think we need a larger filter, though. The flow is okay in the one we have going but I don't think exchange rate is good enough.
Oh, and we change out about 20% each week.
Oh, yes, I mixed the two up. Nitrates at 20ppm and nitrites 0.