Demonstrating just how much the industry has changed, Digital Goldfish released its first mobile game in 2005. It was monochrome baby simulator for Java phones called BabyGrow.

It was not successful.

Seven years on, however, the developer's been acquired by longterm partner Ninja Kiwi, having found plenty of success with the iOS and Android games it's made based on Ninja Kiwi's Bloons games.

With that licensing agreement about to time out, this proved to be the opportunity for both parties to look towards a synergetic future.

"The deal's been the cards for awhile," confirms Digital Goldfish's MD David Hamilton.

"It made sense for Ninja Kiwi to bring our mobile expertise inhouse and for us to work even more closely with them for the future."

Half a world away

Despite their geographical separation - Digital Goldfish in Scotland and Ninja Kiwi in New Zealand - the companies share a similar background.

Both were set up in the mid-2000s by twentysomething co-founders. In the case of Digital Goldfish it was Hamilton and fellow University of Abertay graduate Barry Petrie.

Ninja Kiwi was started by the Harris brothers, Chris and Stephen.

All four are now involved in the combined 35-strong operation, making games for web and mobile.

Pop! Attack!

For Digital Goldfish (or Ninja Kiwi Europe as it will now be known), next up is Bloons TD 5 on iOS; the latest release in the tower defence line of games.

The previous title did over 1.5 million downloads despite being priced at $2.99, but perhaps that's not so surprising given the Flash version of the game get around 5 million monthly players.

Indeed, the various Bloons games have been downloaded more than 8 million times.

"It's very popular," Hamilton says. "Even on DSiWare, Bloons TD 3 was a hit, #1 in Europe and #2 in the US, while Bloons TD 4 did 100,000 paid downloads on Google Play."

It was also a top 10 paid game on Amazon's Appstore for Android and the Barnes & Noble Nook tablet.

Yet the future isn't just about Bloons.

Ninja Kiwi has other web games that have come to mobile, such as SAS: Zombie Assault, and plenty more than could make the transition. Similarly, Digital Goldfish has its own IP in development for mobile and Facebook, including a point-and-click adventure.

Their future success together will be all about how well they integrate those two activities with the buoyancy of Bloons.