Celebes Halfbeaks - Information Welcome

A friend of of mine bought me what are supposed to be a paif of Celebes Halfbeaks in return for looking after his daughters hamster. He knew I was after something for the top layer of my tank and this is what the local shop recommended.....
 
I've done a little research but can't seem to find out a great deal about them. There seems to be differing views on how you tell a male and female apart and how big they will grow. When introduced one had a hint of yellow on it's tail, red fins and a black line under it's beak while the other was silvery white, but has since started to gain some colour in it's tail and fins but doesn't have the black line under the beak.
 
The less colourful one (thought to be a female) of the two does like chasing the other one, so much so that the more colourful one seems to try and avoid it. Equally they spend some time together hanging in the flow of water and bubbles from the air block on the waters surface.
 
They seem fine taking flaked food and frozen blood worms and are fine with my cardinals and rummy noses.
 
I need to get some floating plants of as other than vallis there is nothing else at the surface for them to hide in.
 
Any suggestions on ideas on how best to look after them would be gratefully received

http/www.fishforums.net/index.php?/topic/109221-halfbeak-red-fin-celebes/
 
This'll be the best place to look.

Thanks,
 
I'd had a read of that and another read just now, I'm guessing from the seems of things I have two female N. Ravnaki, as they both have curved beaks, while the colours may be varying slightly as they are settling in although I'm still not 100% certain.

I've found halfbeaks to be very sensitive fish, despite being aware that sudden temperature or water chemistry changes can have dire consequences, I gradually lost the whole adult group and all I have left is the single youngster born during the 2012 F1 Italian GP (another was born but lasted a second before being cannibalised).
 
My tips would be...
Long slow acclimitisation to new tanks (I pierced their transport bag in the tank a lot and let water diffuse for ~2 hours)
No more than 10% water changes at any one time (which might mean doing small changes almost everyday to effectively do a 50% change per week)
Floating plants
Well defined edges of tank (plants, dark backing etc.) where possible to try and prevent full speed crashes (and following beak damage)
A secure tight fitting lid!
No small, streamlined tankmates
No hard, dry foodstuffs that are of a tempting size for them to try and swallow whole (one of mine had a badly damaged mouth after an algae wafer incident) 
 
Getting a proper ID for many halfbeaks can be a nightmare, let them settle in for a few days and then get some photos once they have "coloured up." Neale Monks has a great page on these fish on his website (but the url escapes me at this moment).

In terms of identifying halfbeaks, this is another good page, written by the same chap (Neale Monks, who Goat refers to in his post).
 
There is a link through from that article to a page on Neale's own website, which I would suspect is what Goat was trying to remember, but the link is broken, which is a shame, because it went into a bit more detail than the article on here.

Thanks for the replies and links.
 
I finally managed to get a couple of photos of the Halfbeaks, I believe the first is a male, with more colour and slightly less curved beak and the last two which are more plain are females.
 
The female one is regularly chasing the male one around the top of the tank, so much so that the male automatically heads in the opposite direction to try and keep out the way. The female also spends some time towards to the bottom of the tank chasing her reflection and occasionally hassling the cardinal tetras.
 
Is anyone able to confirm which species of halfbeak I have and whether I do indeed have a male and female?
 
Thanks in advance.

Dermogenys spp., perhaps D. pusilla? http/www.seriouslyfish.com/species/dermogenys-pusilla/ (going on the long straight lower beak)
 
Look at each halfbeak's anal fin to determine sexes, males have an andropodium, which works similarly to that of more common livebearers