help required, mold/algae/moss??

[joltz]

I have a small 20Gallon (80Litres) community tank with approximently 18 fish all living peacefully in a oasis i have created for the past year, peacefully that was until the last 2 weeks that its.

Tank conisists of:

1 Gold Gourami
4 neon Tetras
2 Columbian tetras
1 Blacknight ghost fish
1 Rainbow shark
1 Albino upside down catfish
3 Guppies
1 Black neon
2 Triangle shapped with long black fin tetras have no clue of theyre names
2 Suckling catfish

There also was, 2 Snails (now deceased)

Up until 2 weeks ago the fish have been getting along fine, they all stuck to theyre own part of the tank, the Gourami did bully alot of fish and it was territorial however it hasnt killed any fish.

Approximently 3 months ago my 2 snails died, it seemd the suckling catfish stuck to them and ate them is my best guess as i seen 1 of em eating it but i did not witness the action thus the murders of the snails could have been commited by any fish and been suckling cast fish scavengers of the tank it may be a possibily they were there to feast on the tasty remains of theyre fellow sea creatures.

2 Weeks ago a green substance has appeared on the glass of my tank on one side, this substance has also appeared on a lovely shipwreck which lays on the bottom of the tank floor and on a wonderfully colored rock which teh fish love to swim thru and about it.
It is in specks all over the above mentioned areas, my guess it could be algae? but then again it maybe moss or mold or something I do not know as it is why i am writing this to enquire and brush up on my knowledge of this wonder.

Secondly, the suckling catfish which use to stick to the glass all day and feed lavishly off it have stopped doing so since this green stuff appeared, I have also noticed that they seem to be attaching themselves allot to my gourami and they have been chasing it around the tank allot, this they never use to do.

Alot of the fish have now become territorial, living in harmony for so long i notice that they now continue to chase each other.

My tank contains a italian made filter/air pump with a charcoal bah and sponge, i cleaned this 2 weeks ago and replaced it with a new charcoal bag. My tank also has a filter under the gravel and on that same system of filter a seperate hose which leads under the gravel miracasouly airs the tank by blowing bubbles through it.

I am completely baffled at what could be wrong, i have tried algae remover and its still there, i am thinking my last resort to clean the whole tank again but i may lose alot of beloved fish in doing so with a major water change.
Also would it work if i got a clean chux cloth and just wiped it off with my hand in the tank or is that a no no??

The Gourami and black tetras eyes are also very very red, other fish do not seem to have this redness around the eyes.

Thankyou in advance to all Tropical Fish Forum users who reply to my dillema in advanced, it is greatly appreciated.

PS: PH came up to around 6.5-7.0 which should be normal.
Ammonia was NOT present, considering the ammonia test came up clean I am presuming that nitrate and nitrite should also be a negative?

 

[cutecotton]

hmm that is really strange besides the green stuff appearing there's nothing else that's different? have you checked ur ammonia, nitrite nad nitrate levels? that might give you some clues

as for WHAT the green stuff may be...beats me, i'd say some kind of algae, but it shouldnt' have that much effect on the tank..i'd check your water parameters and hope for someone more expierenced to come and see if they have a clue

 

[kgrehm]

Was there any delay in any of the water changes, or difference in more or less sunlight?? Also just curious you said a 20gal. tank with 18 fish. Seems a little crowded if you ask me.

 

[joltz]

Yeah there was a delay in a water change, i was away for 2 months and never changed it, during that time i left the light turned on and when i came back i found the light to not be working after it blew, for how long im not sure, it could have happened the day i left or the day i came back.

There would have been no other light source hitting the tank because i left my blinds closed.

It sounds crowded but when i look at it it seems like i can for more!

 

[kgrehm]

I would believe that is your problem. If you dont do regular water changes and the lighting is thrown off there is a pretty good chance for alge to grow. Especially in the amount of time.

 

[tstenback]

PS: PH came up to around 6.5-7.0 which should be normal.
Ammonia was NOT present, considering the ammonia test came up clean I am presuming that nitrate and nitrite should also be a negative?

Never presume that if you have 0 ammonia that the nitrite and nitrate reading will be zero as well. Ammonia is the first part of the nitrogen cycle, it is followed by nitrite which is then changed to nitrate. The nitrite part of this is the longest part of the cycle and is often at its highest when ammonia has already disappeared. Also nitrates continue to accumulate over time and if you have not done a water change in 2 months i would guess that the nitrate level may have been quite high. Nitrate is also a major contributor to algae growth and with the extra light i think that is what your problem is. Keep up the water changes and manually remove as much of the algae as possible. Your catfish dont eat all types of algae so perhaps this is one of those types they dont like. HTH

 

[joltz]

is there anyway to tell if your nitrate nitrite is high? IE is the water murky or cloudy?

Ive noticed since i came back and the water change has reduced this algae now to, its still there but not as prominent as it use to be, manually you mean just wipe it off with a clean cloth/sponge from inside the glass should be fine?

 

[tstenback]

No there is no way to tell by looking at the water. Although one of the by products of high levels of nitrite is a bacteria bloom which will cloud your water but will go away by itself after a few days or so.
Yes just use a sponge or cloth to wipe the exisiting algae away and control the amount of light. Good Luck