Why do the polyps on these birdsnest corals look different? (pics)

[fronty]

I have two birdsnest corals. One is a pink lemonade and the other is a green ORA. The polyps green one are a lot bigger and the skeleton is thicker. I can barely see the polyps on the pink lemonade and it is growing really thin. I have a lot of flow in the aquarium.

These photos are taken from the about the same distance.

 

[markalot]

The first one appears to be almost dead, the dark areas are dead IMO.

There are numerous varieties of birds with different branch thicknesses and different size polyps. The polyp structure is the same but the size and colors are different.

 

[Reefvet]

The top one looks like it's dying, or at least parts of it have. The second one looks healthy.

The first one doesn't look like any PL I've seen but that may just be the photo. If that is in fact what it is, it needs more light than the Seriatopora caliendrum

 

[fronty]

I've had the pink lemonade birdsnest for a few months. I went through an alkalinity issue that caused some bleaching. Here is another pic with just white light

 

[markalot]

Alk issues can quickly kill that type of birdsnest, but in good conditions it's a fast grower. Those branches look dead, so you might want to frag the live areas and start a new colony.

Here's a similar birdsnest of mine. I reduced this to a small frag and this is siz months of growth. I recently had a phosphate issue and Alk spike that killed off some of the interior branches. You can see the white areas near the center. Also notice the white tips at the end of most branches. These are growth tips and it lets you know when the coral is happy.

 

[Ckyuv]

The top one is doneskis, the bottom one looks good