Why Is My Lima Shovelnose Always Shedding His Slime Coat?

[xenomorph]

Hi...we have a 180 gallon aquarium, among others. The 180 houses a lima shovelnose (about 4 years old, 13"), four juvenile jaguar cichlids (we plan on giving away two and keeping a pair), four plecos (two gibbiceps, one liposarcus, one rhino), two young senegal bichirs and a spotted raphael cat.

For the past couple months our lima has been shedding his slime coat quite often. He will go through days where he will look quite bad (even his 'feelers' will look frayed) then he'll go back to looking good again. He used to be quite beautiful and healthy so I'm not sure what happened here. He is fed raw fish, shrimp, krill, and large earthworms--krill being the primary aspect of his diet.

We change 30% of the tank's water every 7-10 days and he usually looks better immediately following water changes.

Temp is kept at about 75-78 degrees and filtration is two Filstar XP3 canisters and a homemade wet/dry (filtration media is about 8 gallons of natural sponge, which resides in the sump under the tank).

Also I have noticed that our largest gibby has some cloudiness--like catracts, almost--over his eyes and so does one of the jags. Both fish are kind of legarthic but still eat and look fine otherwise. I have tried to find info on all this but it leads to ick and other things that the fish don't have.

Everyone else in the aquarium looks and acts healthy. The jags are quite active and for the most part they don't bother the other fish However, yesterday we noticed one of the jags nudging the lima. But I think this was because the lima was staying in one position of the tank and normally he swims around. The jags can be quite curious and will nudge or mouth things to check them out. But they are not constantly harassing the lima, by any means.

 

[Darkstar]

It's hard to say withough seeing stuff like the water parameters etc...

However I think there's a big clue in this sentence:

We change 30% of the tank's water every 7-10 days and he usually looks better immediately following water changes.

Have you tried doubling the frequency of the water changes to see if that solves it...perhaps your filters are no longer enough to filter all the waste produced in the tank?

I'd firstly try upping the frequency and go from there.

Darkstar.

 

[CFC]

Check the pH and if you can the KH too, also check the pH and KH of the water you use to top the tank up for water changes to compare the results. With that many messy fish in the tank i would suspect a build up of dissolved organics in the water which would show itself as a falling pH and low KH of which symptoms shown by the fish would be loss of colour, lethargy and cloudy eyes. If this is the case the answer is larger and more frequent water changes, 40% at the weekend and a 20% change midweek.

 

[xenomorph]

Thought our water testing kit had a KH tester but it doesn't. However, pH in our regular tap water is 7.2 while it's 6.1 in the 180. It's also about 7.2 in the other aquariums. Why would it be lower in the big tank? We don't treat the water any differently.

Should I add some Melafix to the big tank? The lima looks a tad better but his 'feelers' are a bit fuzzy I've had great sucess with Melafix in the past but never used it with catfish before.

 

[pica_nuttalli]

its because the waste from so many larger fish builds up more quickly in the large tank. i suggest that you re-read CFC's post.

 

[xenomorph]

Sorry, my husband is the one that initially relayed back to me what you guys responded and he left that part out.

We're planning on doing our big water change on weekends and a smaller one during the week.

The big one will be tough though, our water heater sucks and just changing 30% drains all the hot water...I guess we will see what happens

 

[CFC]

Decaying matter releases organic acids into the water, these acids dissolve the calcium buffers (KH) which stabilise the pH of the water and as the calcium dissolves the water becomes more acidic.

The trouble really begins when you start to do water changes with water with a higher pH value, the new water raises the pH again and the buffers stabilise it for a few days until the acids start to eat the calcium away again and the the pH drops like a stone again, an unstable pH is extreemly stressfull for fish and as we all know stress is the biggest killer of aquarium fish of all.

As for the big water change dont worry too much about keeping the tank temperature the same, fish will happily take a drop of up to 4 degrees celcius so as long as your tap water isnt really cold then just filling the tank slowly using a hose wont cause any problems, just keep an eye on the temperature as you go and if it does start to drop a bit too low stop and allow the water to heat back up again before you continue.

The best thing you can do for your lima is get the water stability sorted out and keep it stable, there is no medicinal substitute for fresh clean water. I would recomend doing 20% water changes every day for a week to get the tank into good shape first before starting on the new maintanance plan.

 

[xenomorph]

Ok we will start doing small water changes almost daily for a week before the big weekend change/smaller midweek change plan.

No one answered my question about Melafix so last night I decided to go ahead and put some in the tank. The lima stopped shedding his slime coat, his eyes are clearing up, and he actually went up to a pleco and nipped it, like his old self, within a couple hours after adding the Melafix. So we will add this daily for 3-5 days along with the water changes.