Belly color : development

I was wondering how old juveniles are when their colors stop developing? Until when do you have the time to give them, lets say a red color ?

I'll assume you're talking about H. orientalis? I think they can be turned red at any time during their life, but the bigger and older they are the longer it takes for the redness to develop.
It might be worth doing a search on the Fire bellied toad section, I think i read a couple of good threads on dietary management for colour development on there.

In the past I've seen keepers suggest that colour is fixed as juveniles due to an early diet low in carotenoids. In my experience this is not the case. If you feed a diet high in carotenoids they can develop strong colour at any stage of life.

I've had good results with Hikari carnivore fish pellets, which turn adult newts from yellow to deep orange if used regularly. Jay at Slimbridge has been getting great results with Repashy superpig, which I'll defiantly be using in cricket feed when I get round to buying some.

Do you ever feed the pellets directly to your newts or are you feeding them to worms/crickets...?

I'm pretty sure they're fed directly to the newts. I have a bag of Hikari pellets, but I've only gotten my newts to eat them once or twice. Right now they're eating whiteworms and nightcrawlers. Mark, what's your method for feeding them to your newts?

Yes
this is a good link , but i was wondering if you can be too late basically...so from what you guys tell me you can change their color during their whole life, thats unbelievable :happy:

AfroNewtkeeper said:

Mark, what's your method for feeding them to your newts?

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Nothing special. I let the pellets soften in water and then usually hand them out individually using forceps. I break them in half for smaller newts and skewer them on a bit of thin wire to feed. I'll admit not all of the species I keep like them greatly. N.strauchii go crazy for them whilst the Ommatotriton turn their nose up after a couple. I could well imagine H.orientalis refusing to eat them. No pellet beats a juicy worm.

Thanks guys, i'd like to try these pellets. You can feed them to any newt species ?

You can definitely change the colour at any stage post-metamorphosis, but as it has already been said, the larger the animal, the more amount of carotenes/time you need. Larvae that are just beginning to develop belly patterns are the ones that require the least effort. Very small amounts of carotenes are sufficient to produce red bellies.

Aside from the pellets, you might want to try other carotene sources like fresh-water crustaceans or even commercial powders which contain canthaxanthin and astaxanthin. They are very effective and require few dosis, the problem is that administrating it to aquatic animals is much more complicated.

The pellets might be adequate for any species depending on the size. Also some individuals accept pellets very well but others might refuse to eat them.

Whether there is a fixation period and the extent to which colour can be added/lost after that period probably depends on species. In Agalychnis frogs, there seems to be a strong juvenile fixation period where very little change is possible thereafter (A brighter future for frogs? The influence of carotenoids on the health, development and reproductive success of the red-eye tree frog - Ogilvy - 2012 - Animal Conservation - Wiley Online Library), but in Mantella aurantiaca (from ongoing work in my lab), it seems that one can increase the redness of animals later, at least in sub-adult frogs after the initial orange colouration has developed, but the effect is less strong than if carotenoids (superpig) are given to newly morphed juveniles.

It might be due to aposematism; Agalychnis use the carotenoids (combined with blue pigments) to produce their green dorsal colouration, and some sexually-selected traits like orange feet, whereas species like M. aurantiaca, Bombina and Cynops use their colours aposematically and hence there is more importance in 'topping' these up throughout life. These species can also fade with age, to a point, suggesting some degree of constant replenishment throughout life. This is just a guess though!

C