This page lists my experiences with Giant Danios. While some of the fish-related Web sites you may find may give you the scientific information, very few of them probably tell you the information in this post. I should point out however that these are my personal experiences, your mileage may vary.
Firstly though, here are some scientific facts and figures:
Scientific name: Devario aequipinnatus
Name: Giant Danio
Size: 14cm / 6″
pH range: 6 – 8
dH range: 5 – 19
Temp: 22–27°C / 72–81°F
From my experience these are most active and easiest tropical fish to keep of their size. The scientific facts above are probably right for this species as I’ve had these fish both in low and high pH tank configurations and those same fish are still swimming around in one of my tanks.
Giant Danios are sort of a dream fish. While you may find them listed as aggressive in some pet stores, I can’t say that I agree. Keeping a minimum of five is probably a requirement to keep them peaceful, and from my experience with five of these fish you shouldn’t really have any problems with most fish (this does not mean that other fish won’t have a problem with them, however).
I have kept (five) Giant Danios with the following aquatic life at one time or another, and had no issues with any of them: Ramshorn Snails, Mystery Snails, Ghost Shrimp, Peppered Corydoras, Rainbow Shark – Shark was aggressive, but Danios were too fast), Oscar Fish (I have not kept a large Oscar with these fish – I suspect the Danios would be eaten), Guppies Female, Guppy Fry, Fancy Male Guppy, Zebra Danios (Longfin also), Common Pleco, Neon Tetras and Tiger Barbs.
That’s a pretty long list of what, for me, have been compatible tank mates for Giant Danios. I haven’t even tried keeping a lot of other fish who might work purely because I kept Tiger Barbs in the same tank for a long time. I am extremely surprised though to have seen Guppies advance to adulthood alongside these fairly large and fast Danios.
Possible aggression: To each other
There’s been a few times when I have spotted one Danio chasing others and I think this is between their own species only (I have never seen them chase any others). This appears to be purely territorial. Most of the time the fish will swim around freely.
These are the most active fish I have ever seen. They constantly ‘patrol’ the middle to top regions of my largest tank and occasionally put on the most incredible ballet I have ever seen: All five of them will group together and circle around with each other, giving you brief flashes of silver and gold as the light catches them. I have also seen them swim while stationary (they will find a place in the tank where the water moves against them and slowly swim along in that current). These fish are also not aggressive feeders, many other fish will eat in a tank before these guys and they don’t seem to have a problem with that.
They are absolutely beautiful swimmers and stunning to look at. I’ve always found them to be non-aggressive (I have five – that is probably the reason for that) and found them incredibly hardy. Like other Danio species, these fish could be good larger fish for a beginner. I highly recommend these fish be used as ‘dither fish’ in a large tank where you’re keeping something like a Common Pleco as a ‘center piece’, their constant activity and patrolling will give much movement while the Pleco is stationary.