Dictyota bartayresiana and Lobophora variegata, blue algae in the reef aquarium.

Dictyota bartayresiana or fork weed.
There are many of the Dictyota family and as with lobophora, most are said to be thalloid as well, like the Lamouroux and Dichotoma variants!
The only reasonable variant is bartayresiana, it’s the least invasive and potentially colourful of all the Dictyota  and near all Dictyota are very invasive in the reef aquarium!!!!
The only issue with this more colourful Dictyota is the aquariums grazers can make it disappear quite quickly, but there is always hope due the base of  most decorative algae species that allows for regrowth, this area is poisonous to near all herbivores!
This algae is found in swell and or current affected sites of medium to high illumination and at least some nutrient, very common at open ocean sites.


More Dictyota specimen photos.
https://southeastqueenslandm.aforumfree.com/t2313-dictyota-algae-reference-photos
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Lobophora variegata, the variegated specimen.
These are usually said to be thalloid, meaning a semi rigid life form or body mass resembling a thallus.
This version of the extremely common Lobophora brown algae, is not overly common and is usually only found in low light areas and of high nutrient content as well.
They are found mostly in either high current or substantially swell affected areas.
Very few life forms graze on this one, in fact I have not seen any prefer it at all, just a nibble from reef aquarium herbivores from time to time!
This one is potentially invasive by coverage but of slow growth potential and does not harm via built in protective chemical toxins or any other defences, their only real defence is being quite rigid and leathery.


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