Thanks for that. Glad to know it's nothing I'm doing wrong that's keeping Mrs BM stunted. Always expected her to be smaller than normal and not "catch up" but she doesn't seem to have grown at all. Maybe I'm being a bit harsh there though. . .
It's been nearly a year since I was last online, but a lot's happened in that time. Have fought hard with a serious eczema outbreak, taken driving lessons, passed my test, and of course, as always, working hard (especially now that I have a car).
Anyway. Last time I logged in, it was really as an appeal for someone with a pond and space for 3 common goldies. In time, I managed to find a pond more locally with a work colleague, and now they're doing well, leaving their blackmoor tankmate on his/her own with his future hanging in the balance, and I was seriously thinking about getting another 40gal tank, and moving him/her over then getting another fancy friend . . .
The BM turned out to be a female and I never did get round to getting another 40gal tank - just didn't have the money.
Luckily, I didn't need to. With only 4 tropical fish left in the 40gal, I swapped the tanks around, so that the BM was in my original 40gal, and my tropical fish are now in the 20gal.
The BM hasn't really grown since I got her :-s but I don't know how old she is.
The fantail was added last week.
(The heater's the original 200w that I used for the tropical fish 0 it's been unplugged now but I just haven't got round to removing it, as this tank's at my dad's )
Goldfish never stop growing - at least on the inside, so being in a bigger tank, he will probably start to grow again physically. It just means he may not to get to his full potential size of 10-12". Stunting is not as simple as the fish stops growing and looks small compared to a full sized fish of similar age. The organs NEVER stop growing, ragardless of what the physical form of the fish is doing, so if s/he's 2" long (or the size of a 6month old BM) his organs are the size of a 2-3 year old fish.
Having Googled your filter, it appears that the crystal is used to remove water discoluration. If so, it's a bit like carbon - it's best use is for removing meds and other impurities from the water, but otherwise it's not really needed. My advice would be to take it out and replace with other media, but keep it handy in case you need to start medicating the tank. The crystals will remove them from the water after the duration of the treatment is over.
The sponge is the media - that's where the bacteria will grow their colonies.
Well done on the upgrade. The BM will be much happier in a 90ltr than in the 13ltr, but I'm afraid I still have some bad news.
1) Goldfish are messy fish and should really have filters designed for at least double the tank size to cope with all the waste, so even your new filter will struggle.
2) FK recommends a minimum of 30gal/137ltrs/36 US gal for a single fancy goldfish (75ltrs is 20 US gallons, btw). This is because anything less than that can result in stunting. If your GF has had the B, for a few years, the chances are, it's already stunted. Please see these links for further advice:
Regarding the filter, the 2 you have aren't going to be up to scratch long term, but for now, you can just cram the media from the smaller filter into the newer one, to save you running 2 filters at the same time. Once you get an even bigger filter, you can do the same again and put the media (sponge/bioballs - whatever's inside the filter) into the bigger filter.
Technically, you'll start to get a small amount of die-back after 20min, but realistically, as long as the filter can be turned on within an hour, you should be fine.
After an hour, you may start to notice an ammonia/nitrite spike so I'd advise to keep an eye on ammonia and nitrite levels for a few days, to ensure they remain at 0ppm, and be prepared to carry out water changes if they start to rise.
If you've experienced a power cut, or are transferring the fish and their tank/filter to another destination for example, you can keep the bacteria alive by putting the filter/media in a bucket of tank water and use a battery-powered airpump to keep the water oxygenated.
The Monday transfer of the commons fell through, but we rearranged for this afternoon, and at 4:40 this afternoon, between work shifts and with me being a bit flustered in the process they went off to their fantastic new home, leaving the BM looking smaller than ever in the tank all on his own.
Skulk wrote: I was worried that there wouldn't be sufficient bacteria for the QT filter, and not enough left for the filter in the DT.
That's why I suggested keeping an eye on ammonia and nitrite for a few days after getting the second batch of fish
Would it be necessary to do greater and/or more frequent water changes while the bacterial population catches up, or is there some margin for error?
It would only be necessary to carry out additional water changes in either/both tanks if you find an ammonia/nitrite spike. If ammonia and nitrite remain 0ppm, all you'd have to do is carry out the weekly water changes as per normal.
It occurred to me that once the DT had cycled, I could move the QT filter into the QT and maintain the bacteria with ammonia until I'm ready to get more fish.
Of course you could. Just as long as you keep the filter "fed" with a supply of ammonia every day.
At the end of the day, it's entirely up to you whether to cycle the QT filter independently of the main tank/filter, but having "borrowed" some media from my main tank for my own QT, I can honestly say I've never experienced any problem with ammonia or nitrite. Of course, the first time I used some of the media, I was nervous in case it didn't work, but I needn't have been. The bacteria are already there - it's not like they have to start from scratch again, so they recover their populations quicker than bacteria establishing a new territory in an unclyced filter.
Assuming the main tank is fully cycled, when the 1st fish go in, you'll get some die-back to accomodate the new bioload. Once you take some media out for the QT tank, the bacterial population will respond and will soon catch up.
If you're worried, just keep an eye on ammonia and nitrite levels in both tanks for a few days