Velvet

[Biulu]

I had heard this before but am now experiencing it myself. Low hardness comes with an increased risk of velvet. What are you guys doing to avoid velvet in your tanks?

[bergenm]

I think low pH, GH & KH can stress some fish out and makes them more susceptible to all diseases. If you are on city water it can be a bit of a challenge.

I keep a bag of crush oyster shell in all of my filters and I find this helps stabilize all three of those water parameters. The oysters shells dissolve in acidic water giving off calcium carbonate which keeps the pH in the 7.0 range.

For my koi, they spend the summers outside in a pond with high pH (8.5), so when the come for the winter, they get stressed moving into city water. I use the oyster shells in two large filters and then dose with baking soda to keep the pH, GH & KH even higher.

The oyster shells have to be replaced every six months or so and the filter bags need to be kept clean so that water circulates (it also makes pretty good filter media).

It is also species dependent, all of my fish prefer a minimum pH of 6.5.

[Gowalkitoff]

I keep fish that prefer soft acidic water, so I have never experienced velvet. For fish that preferred neutral to alkaline water, I had put a media bag with some crushed coral in the filter. I then tested the tank water pH twice a week and adjusted the amount of crushed coral in the bag until I foung the ph I wanted to hold. Needless to say that was too high maintenance for me, so I now keep fish that suit the water I have, and me and my tank are happier about it.

[Biulu]

Thanks! The fish in the tank like acidic water and they are actually in an almost black water set up with driftwood, elder cones and lots of mulm. But this is the second batch of the same fish that gets velvet after about 6 weeks being in their tank in my water. I had hoped it would be easier to keep these fish in Ottawa water, but apparently not so much.

[Gowalkitoff]

Wow. Sorry to hear about those difficulties. I have no advice, I've kept planted freshwater tanks in Ottawa for almost 20 years, no velvet, not on purpose. Could it be the livestock source?