Cory Concern

[newfin]

Hi to everyone that may be able to advise me.

I have a new 150 litre tropical tank set at 26 degrees. Been running for about six weeks now. Started with 6 leopard danios then added 4 Schwartzi corys and 4 punctatus corys just over 3 weeks ago. Am concerned as have noticed today that one of the punctatus has a couldy film over one eye, otherwise is with the others acting normally. One of the schwartzis has a red barbel as well but I think I can rectify this by providing a sand area for them. I currently have smooth 1-3mm Roman pea gravel.

Water levels are still settling - daily changes of 30-50 litres for the past 3 weeks to keep ammonia down.
last tests using API liquid master test kit
High range pH test - 8.0
Ammonia -0.25
Nitrite - 0-0.25
Nitrate - 5-10
Temp 26 degrees

Will continue to do daily changes of 50 litres and see if things improve and provide sand area within next couple of days. Should I do anything else in the meantime? I've been really worried that the tank still hasn't settled but thought that it may be getting there slowly.

Many thanks

 

[Colin_T]

The cloudy eye could from water quality or the fish damaged it on some gravel or other object in the tank. You shouldn't really put catfish or loaches into a new tank until the filters have settled down. Any ammonia produced while the filters are developing is very toxic to fish and catfish are more sensitive than others because they don't have scales to protect them. The combination of ammonia and a high PH will make the problem worse. Ammonia is toxic in alkaline water (PH above 7.0) and if your PH is 8 then any ammonia present in the water will be lethal to the fish.

Some test kits will read 0 ammonia as 0.5 or 0.25 so you should check your tap water and see if it reads 0 or .25. If it reads 0 then your tank still has ammonia in the water that isn't being broken down by the filters.

If the water is fine and the fish healthy, a slightly cloudy eye, (caused by a scratch) should clear up in a day or two without any medication or intervention from you.
If the water quality is good and the eye hasn't cleared up in a few days it might have a bacterial infection, in which case you will need to medicate it. However, try to use something that doesn't affect the filter bacteria and is safe for scaleless fish like catfish.

The red barbel can be from poor water quality or a bacterial infection.

1-3mm smooth gravel is fine for cories but they do prefer sand.

 

[newfin]

The cloudy eye could from water quality or the fish damaged it on some gravel or other object in the tank. You shouldn't really put catfish or loaches into a new tank until the filters have settled down. Any ammonia produced while the filters are developing is very toxic to fish and catfish are more sensitive than others because they don't have scales to protect them. The combination of ammonia and a high PH will make the problem worse. Ammonia is toxic in alkaline water (PH above 7.0) and if your PH is 8 then any ammonia present in the water will be lethal to the fish.

Some test kits will read 0 ammonia as 0.5 or 0.25 so you should check your tap water and see if it reads 0 or .25. If it reads 0 then your tank still has ammonia in the water that isn't being broken down by the filters.

If the water is fine and the fish healthy, a slightly cloudy eye, (caused by a scratch) should clear up in a day or two without any medication or intervention from you.
If the water quality is good and the eye hasn't cleared up in a few days it might have a bacterial infection, in which case you will need to medicate it. However, try to use something that doesn't affect the filter bacteria and is safe for scaleless fish like catfish.

The red barbel can be from poor water quality or a bacterial infection.

1-3mm smooth gravel is fine for cories but they do prefer sand.

Thanks for your advice - I didn't know about the pH effect so I will get hold of some API pH down tomorrow. I have just tested some tap water and levels remained at 0, compared to the tank at between 0-0.25.

I was considering trying to obtain some bactinettes as previously recommended to boost the filter culture but would it be best to keep an eye on the Cory's health first? I realise with hindsight that we put the corys in too soon but we hadn't had any advice to deter us up to that point. If I knew then all that I have learnt from this forum I would have done things differently.

I will also provide them with a sandy area to keep them as happy as I can.

Would a reliable local aquarium shop be able to supply the necessary medication if required? I'm really anxious of not getting decent advice from fish shops given the experiences I have had so far.

 

[rhostog]

I would advise against trying to lower the pH by adding stuff out of a bottle. Adding chemicals to adjust pH often only has a temporary effect, especially if your water is hard (IME it reverted overnight), and the fish will be much more stressed by the swings in pH than by leaving it alone. Water changes are the best way to get the ammonia and nitrite down as low as possible and keep them down.

Small smooth gravel like you've got should be OK for the cory, and the redness is more likely to be a result (direct or indirect) of the ammonia in the tank. If you do decide to add sand, check that it's not going to affect the pH (some types of sand will raise the pH even further).

Very sorry you're having such a hard time. It will get easier once the tank has fully cycled - but afraid it might take a while yet. Is there no way you could take at least some of the fish back to the shop?

 

[newfin]

I'll concentrate on the water and continue the daily changes to keep the ammonia down. Fish seem ok in themselves this morning, certainly no worse but I am worried about these changes in their health. Hopefully with improved water quality they will recover. Thanks for the advice, i'll keep you posted if that's ok.

 

[jollysue]

I have not read this carefully, but it sounds like infections. Possibly cloudy eye and barbel infection.

Vacum your gravel thoroughly, do small frequent water changes, reduce feeding. Corys are a bottom fish. If the substrate is not kept clean (and gravel can be a problem here for food and other stuff to slip into the crevices and rot) Corys can get barbel infections. Usually they can recover with just a good tank and filter maintence schedule. The fact that there are both red barbels and an eye issue suggests that there is a tank issue.

I agree, do not mess with the pH. It is better to keep it stable unless you have very rare and sensitive fish. High temps also raise the ammonia toxicity.
temperature and pH effects on ammonia and nitite toxicity

Corys are a very hardy and forgiving fish in the whole. They generally can handle a minor cycle and recover.

 

[newfin]

many thanks jollysue. I have been doing daily water changes and vacuum a section of gravel each time so hopefully it should be fairly clean. I did raise the temp from 24 to 26 degrees in the past couple of weeks, and as you say warm temps can add to problems so I may readjust this, especially as 26 is probably the upper limit anyway? I noticed that the little cory with the cloudy eye also has a small white patch on the top of it's forehead which may add to the liklihood of infection. I will continue with 30% water changes and water tests to keep the ammonia, and nitrite down and see what happens over the next 24-48 hours. Many thanks again.

 

[newfin]

Thanks everyone. Just to let you know, both cory's are doing very well. Both are almost back to normal. After vigilant water changes I acheived zero NH3 and NO2 which have held over the past 12 hours. I have just finished another change. Total readings are:

Temp 24 degrees
NH3 - 0
NO2 - 0
NO3 - 5-10

I am so happy they are better, couldn't have done it without this great forum - thanks so much.