Tank Progress

It's looking good 

That many danios in that volume of water shouldn't cause very high levels of ammonia or nitrite. But be careful about the timing of getting new fish. Wait until you are sure you don't have any ammonia or nitrite before getting the next batch.

The old stocking rule was 1 inch of fish at adult size per US gallon of water, for slim bodied fish that grow no bigger than 3 inches. The corresponding fish-in cycling rule was 1 inch of fish.....per 5 US galls etc.
So if we stick to that as the absolute maximum, that's 1 inch of fish per 19 litres water. Your 480 litres will take a max of 25 inches of fish, or 63.5cm.
Zebra danios grow to 40 to 50mm (from Seriously Fish), call it 5cm to be safe.
63.5cm = 12.7 danios.

Your initial choice of 10 to 15 danios is spot on 


Each additional batch should be no more than one third of the body mass of the fish already in the tank. Obviously as the amount of fish builds up, the body mass of allowed new fish will get bigger. One reason for saving the bigger fish till later. The other of course being that it gives the smaller fish chance to grow to a size the bigger fish can't eat.

I have ordered some more plants colin,so there will be 3 more in there,the background
Is a stone effect,generally happy with the tank,waiting for a new digital thermometer to
Come as the last one was faulty,but suprising how cold the water feels even though both
Heaters are set for 26 degrees,another couple of days and the first fish will go in

I don't know why anyone would want to put the tank temp up to 26. Practically all our fish would be perfectly OK at 23, or even lower. Increasing temperature speeds up the metabolism of fish, which potentially shortens their life span and increases stress levels. It's important to not be anthropomorphic "I like to be nice and warm and so my fish will also be happier the warmer they are". So long as fish are kept within their acceptable range, the lower the better. Most fish breed at higher temperatures  and so keeping them at these temperatures all of the time can mean that they are in permanent breeding mode, which they should normally be in only for a short period of time. This may be why some males permanently chase and harass females and show aggression among themselves.
Over the years, the "recommended" temperatures for fish seem to have steadily risen, though there seems to be absolutely no real evidence to support this. All of my tanks are kept at about 23 and the 16 species of fish I have so far all seem perfectly happy, showing normal appetite and other natural behaviour. I don't believe most danio species would be comfortable at 26. People seem to be afraid of "chilling" their fish but don't concern themselves enough about the upper temperature limits.

Shipwreck -

You'll find most forums now disapprove of fish-in cycling, instead recommending fishless cycling using ammonia.
Shops normally either recommend fish-in because that's what they've been doing man and boy and don't hold with fishless; or say both fish-in and fishless are old fashioned, just use this bottled bacteria because they want your money or don't think their customers can understand anything else.

Fish in cycling, done properly, is not cruel. What is cruel is putting a lot of fish into an uncycled tank, never testing the water or doing water changes, and just hoping some fish survive. This is the old way of cycling a tank, something you'll still see advised.

Filter squeezing is better than nothing but only helps slightly. This is because the filter bacteria grow in the biofilm and only tiny amounts of biofilm are dislodged during squeezing. If a lot was lost, we'd have to re-cycle our tanks every time we washed the filter media.

Neon tetras used to be hardy little fish. Fish breeding is big business and the conditions the fish are bred in are less than perfect - resulting in fish that don't cope well with a fish-in cycle. It is not unknown for them to treat their breeding tanks with antibiotics on a continual basis to keep illness at bay. When these fish are removed from their antibiotics, they get sick easily.

I have cherry barbs too, and think they're lovely and characterful. I also have lemon tetras and diamond-head neon tetras, and they're all perfectly happy at 22°C.

Richard isn't digging at you at all.... it's just that we get a bit exasperated at the rubbish the staff in fish shops tell people, and it sometimes comes over in the posts as the written word can be interpreted in many ways.

There's a really good article on tank temperature here.

very interesting article there  colin with plenty to think about.

No worries Richard,i have taken the 150 watt heater out of the tank and i am slowly going to lower the
Temp to around 22 degrees,as it is early days i have 12 cherry barb and the other 6 i went back to the
Shop and reread the label and they are dwarf golden barb/golden dwarf barb,lovely fish but according
To seriouslyfish i should not really have them at this early stage,so this is what i mean with regards to
Conflicting advice and he was happy to point out that he is a 30 year plus fishkeeper

Hmm think I'll turn my heater down too!!

I think that's the gist of the article, that you set your tank heater thermostat at the lowest you want your tank to get to. So, say if you set your tank thermostat at 19°C, then if your lounge temp fell below that, then the rank heater would kick in. I don't think it's advocating doing away with the heater all together.