Bolton Aquarium raises more tiny fish


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Aquarists at a British aquarium who were the world's first to breed a tiny cyprinid have successfully raised fry from their offspring.

Pete Liptrot and Paul Dixon of Bolton Museum Art Gallery and Aquarium were the world's first aquarists to spawn the miniscule Danionella species.

The myanmarese fish, which is one of the smallest known to science, now share their tank with multiple generations of fry.

Wild adult males measure just 12mm, with females reaching just 10mm.

In an exclusive interview with Practical Fishkeeping, Pete Liptrot explained how the Aquarium had managed to spawn the tiny fish.

Educated guess"I could say it was a very carefully planned research programme", quipped Liptrot, "but we just put them in a tank and gave them what we thought they would need - and they spawned."

"We've got good water in Bolton. It's soft and it goes acidic very easily, although it comes out of the tap slightly alkaline. The pH doesn't last, so you can mould it to more or less what you want."

The Aquarium obtained the Danionella from specialist retailer BAS earlier this year.

None of the members of the Danionella genus had previously been spawned and were rarely kept, so very little was known about the fish.

"It was really a case of trying them in a variety of ways and then setting up in the most naturalistic manner we could", said Liptrot.

"We didn't know whether they'd be depositors, like Sawbwa resplendens, or scatterers like Zebra danios. So we gave them Java fern in case they were depositors and Java moss in case they were scatterers.

"The idea was that, if they spawned, there was enough cover there. We assumed that with a dozen 10mm fish in a 30" tank some would come through."

The first batches of fry were noticed in June 2006 and proved challenging to raise, given their tiny proportions.

Poorly knownThe small size of Danionella species means that few have been identified or studied by scientists.

"If you imagine most of the techniques used to collect fish, you'll see why these are so easy to overlook", explained Liptrot.

"The fish are not actually true Danionella translucida. We've called them Danionella cf. translucida, instead. I wouldn't actually be surprised to find that there are actually 20 species in Danionella."

Danionella are believed to be at risk of extinction through habitat destruction.

Like the recently discovered Paedocypris, these miniscule cyprinids also often occur in very vulnerable parts of south east Asia.

Other successesThe Aquarium had another world first in October when it became the first to breed the newly discovered Microrasbora sp. "Galaxy".

Aquarists at Bolton Aquarium were among the UK's first to obtain this species, which was only discovered in August 2006.

They had had the fish in captivity less than two weeks when they announced that they had seen the first fry in the tank.

This tiny cyprinid, which is also from Myanmar, has been one of the most talked about ichthyological discoveries of 2006.

For more information contact the aquarium on 01204 332200.

Bolton Museum, Art Gallery and Aquarium is situated in Le Mans Crescent, opposite the Town Hall. Opening times are 9am to 5pm, Monday to Saturday and admission is free.