Sick-lids

[Jondur]

hi,

I've a 75 gallon mbuna tank. Currently running Fluval 305 and internal filter. I reckon there's about 20 mbuna of varying size (1 inch to 4/5 inches). Everything was running fine until the other day I noticed that the fish were all at the water surface gulping air. I did a water change and things improved. It happened again so I did another water change and added AMMO-LOCK. Again things improved.

Then catastrophe! Came back from work last night and my pride and joy Venustus (beautiful specimen) was dead, all the others were at the surface and the other big cichlid (not sure of species - I call him boss hog) was struggling majorly - he had even lost all his colour! Gone from black to white!

So I quickly did a big water change and he recovered almost immediately. So what could be wrong? My theories:

a) I'd added some river rock which I'd scrubbed and soaked previously. Maybe I hadn't soaked long enough and there were some toxins leaching into the tank water. I've removed the rocks now to be on the safe side

b) the tank has a high height to depth and length ratio. Maybe the water wasn't oxygenated enough? The water change would cure this in the short term by agitating the surface. Should I get an air stone? Maybe this would explain why boss hog recovered so quickly? Surely if it was a case of the water change diluting toxins the effects would persist for some time?

c) a combination of the two - a bacterial bloom from the rocks using up the oxygen? Maybe airstone plus antibiotics?

I'd appreciate your thoughts. Please let me know if you need any more information.

thanks

 

[Rawimpact]

could have been gases trapped in the substrate

 

[Jondur]

No. I got 'special' chichlid substrate. Came sealed in water-filled bag. Anyway it want in at the same time as the rocks so shouldn't have had time to develop any anaerobic pockets?

 

[Jondur]

hah! you edited your post and now mine seems really rude! Apologies for that. I can't work out how to edit mine but: How quickly would nasty anaerobic stuff form in the substrate?

 

[navygirl76]

how long has that tank been set up? you said you have about 20 fish ranging from one inch to 4-5 inches? im so sorry you lost the venustus, but in the end he would not have been appropriate for a 75 gallon. i have just ONE in a 90 gallon tank, and no tankmates, he is about 9 inches or so long..

what exactly are your water parameters? ammonia, nitrite and nitrate levels? my guess is the tank is not cycled, or overstocked. if i were you, id add a bubble line, test my parameters, do a 50 percent wc a week, and if that tank is overstocked then thin the stock down.

best of luck to ya! i hope things go okay..

 

[Jondur]

how long has that tank been set up? you said you have about 20 fish ranging from one inch to 4-5 inches? im so sorry you lost the venustus, but in the end he would not have been appropriate for a 75 gallon. i have just ONE in a 90 gallon tank, and no tankmates, he is about 9 inches or so long..

what exactly are your water parameters? ammonia, nitrite and nitrate levels? my guess is the tank is not cycled, or overstocked. if i were you, id add a bubble line, test my parameters, do a 50 percent wc a week, and if that tank is overstocked then thin the stock down.

best of luck to ya! i hope things go okay..

Thanks for your reply. The tank has been up and running for well over a month and the filters were from another mature tank. Water parameters are fine. The fish were all fine up until the day before yesterday.

I didn't know Venustus got that big - I say about 20 buts it's impossible to give an exact number as I had six and then one had fry - twice! I had to get rid of the female to stop me ending up with hundreds! the little chaps spend most of their time hiding so I could have anywhere between 12 and 20 fish in total!

 

[mike dunagan]

What is the temp? I would add an air stone asap as well. A month is enough time for toxic gas to gather in substrate.

 

[Jondur]

What is the temp?

errr about 26 celsius. So not too warm.

I would add an air stone asap as well.

So in summary, you guys think it is most likely to be a lack of oxygen problem? Rather than toxins from the rock? How long do you think I should soak the rock for to be on the safe side?

A month is enough time for toxic gas to gather in substrate.

Should I stir the substrate between water changes then?

Thanks again!

 

[mike dunagan]

Yes always stir with water changes! I soak for three to four days. Clean off the outside again and clean with some vinegar. Then soak another day. Remember higher the temp less oxygen the water can hold.

 

[cchhcc]

Sounds like a classic filter crash or uncycled tank to me. Ammonia poisoning likely.

You say the filters were from another tank, but unless the bioflora in those filters was handling the same bioload in that other tank it wouldn't be enough.