GrahamC

That's my question .... if the chemistry is fine, should I worry that I have so much detritus. I had a gravel substrate in my goldfish tank and I had the same issue. I could never clean the gravel without taking too much water out. But once I changed to sand, I could see where it all lay, and could easily siphon up those sore thumb areas. And if you create dead spots in the tank, then the stuff tends be moved into that place making it much easier to remove.

It's a tank maid pro 700 http://www.aquaticsupplies.com.au/blue-planet-tank-maid-internal-filter-pro-700.html so rated for 700l/hour. I am also running the venturi so it's running a little less than that. I also have 6 guppies, and I added 3 baby bristlenoses last week :facepalm: I've been doing 20% water changes every day to try and clean the gravel. Makes me want to change to sand!

Sure, bacteria will be there ...just not the ones you desire. The fact that you do observe any gas pockets indicate that you have significant populations of anaerobic bacteria present ... And in pre-filter days as in China 700AD, they did frequent water changes to keep the fish alive.

I got a complete 60L tank with fish ( fancy guppies, blue gourami ) off TM, and the tank is cycled. There are also various ferns which are weighted down by lead but nothing planted as such. Now, everytime I suction the gravel, heaps of fish crap comes out. If the filter is coping, how hard should I try to clean it so that vacuuming yields no crap and no detritus?

you could just take some sand out and wash it to see if it clouds the water ....

what about applying some hydrogen peroxide to the fin rot?

I think that is contrary to what the experts say. The surface area of a sandy substrate is not that great compared with your standard noodles, and pot scrubbers. I see pockets of gas developing in mine indicating anaerobic metabolism. Now, if you fluidized the sand, that is an entirely different matter :smln:

I have silica sand from Placemakers and I don't have an issue with clouding ....though I thoroughly washed it first. And yes, it's not very white ....

And then you can attempt to treat the specific organ failure ... but arguing senescence as the cause would imply no cure is available.

Old age is not a sickness in itself :smln: With senescence comes impaired immunity, and neoplasia, and general all round reduction in organ function. Since the fish appears wasted, maybe it's an indolent bacterial or viral infection or parasite?

Yes, Port Nicholson.

My sand settles immediately so perhaps it's dirty sand? Although if this is a new tank which has not cycled it could be a heterotrophic bacterial bloom.

But this new tank lacks a biological filter only running for a couple of days. Even with 65% old tank water, that is not going to help much as good bacteria are not in suspension but adherent to surfaces.

If the tank is a standard shape, there is no film on the surface, and there is surface movement, the oxygen levels should not suddenly change. Presumably you're not using a water source such as RO or boiled water both of which deplete O2. And your other fish is not stressed. So, it must be something else.

Isolate ASAP and treat for fin rot ... imho.

There seems to be a huge variation on the prices of 2nd hand tanks. I need a tank for my new office in Napier and I suspect I am going to have one custom built. The architect has planned for one 1650 x 45 x 45 and a glazier in Napier quoted me $2400 in 10 mm glass. Another glazier in Wgton quoted me $300 though it would cost me extra to have it crated and then delivered. The latter also said he coud build a steel frame and let my cabinet maker cover it so it matches the office kitchen. And then I see tanks on trademe 2.4m long for $890, and smaller ones here for even more. So, how does one calculate what an appropriate price?

I read that those stress coat products work by adding some type of irritant to the water to induce the fish to secrete more of the slime. If there have been no changes in water parameters for a long time, and no new fish introduced for a long time, then one might deduce that the fish is sick from a bacterial infection, and less likely a parasite or worm, and that is why she is losing her slime coat.

I read that you need a filter that can do 10x the water volume per hour ie. 4000L/hour. But it also depends on what the bioload is.

How about greasing your arm in vaseline first before immersing in the water?

I got the 2000L/hr model with the UV light, and it's pretty silent unless you have the spray bar above the water line :thup:

And here I thought snails evolved to be goldfish food!

Where?

Water has much more latent capacity than air so I think it will just keep the air at the same temperature as the water.

Being new to these things, I hadn't realised that there are power filters with venturi ports for bubbling the water. This seems to be an ideal solution. I can put the air inlet at the top of the tank above the water line, and below the sealed airtight lid. The filter then goes at the bottom, and bubbles the air back into the water column in a closed circuit so that the water level should not drop. And if water gets into the air hose, it won't matter.

Not well known I guess. I picked up a small tank yesterday whose owner's goldfish had died. Buried in the 2 inches of dirty gravel (poop) was a 10 cent piece from 2006 ( iron alloy ), and a rusty nail!