Prune macroalgae that have branches?

Dear, when transplanting seedlings from one place to another, it is desirable, in order to avoid losses, to prune the branches with leaves to avoid dehydration. Is this procedure important in the case of macroalgae?

That is, is it interesting to prune the branches to stimulate budding, as is the case with Sargasso, for example?

Or is it totally contraindicated?


New member
Interesting question. As you may know, pruning is often done on (true) plants to:
- remove dead/dying branches and other infection courts
- to train the plant's form
- encourage growth elsewhere on the plant
- discourage growth

Though macroalgae don't suffer from disease, that I am aware of, you could sure prune for some of the other above reasons. Granted, algae don't have specialized tissues so you cannot remove new fruits to encourage bud development and flowering, as you would in roses. And you cannot 'train' growth form in algae so much as you continually shape it (algae don't have specialized tissues that provide for structure)

And of course you can prune for nutrient export. Or to alleviate stagnant growth owing to nutrient limitation.

So in your example, you wouldn't stimulate new sargasso growth as you would when you cut your lawn. Your lawn's grasses have carb stores that allow a rapid flush of growth after trimming. Algae don't have localized stores of energy. If you remove half the plant, you remove half the energy store (as well as half the potential growth). You'd only stimulate growth if the algae was nutrient deficient prior, because there are now more nutrients per gram of algae.

Michael Hoaster

Registered Seaweedist
Premium Member
I agree with JZinCO. I don't think it would benefit individual plants to prune them.

However, cutting plants to 'hedge your bets' is a good idea. Here's what I mean: You get a new macro algae, and you don't know what its preferences are, regarding light, current, etc. So, you cut the plant into three equal parts, and plant them in three different areas of your tank, to see where it is happiest. I think this is a good strategy.

I don't think you will see a lot of growth until you feed your macros. If you don't want to add fish yet, you could just add fish food for now. Now is also a good time to build up a detrivore community and clean up crew. They will help convert the fish food into plant food.

It's a tricky game, at this young stage of your tank's life. You want to keep nutrients low, to discourage micro algae growth, but your macros need nutrients too. And just to make it even more tricky, micro algae are more efficient at nutrient uptake than macros! But you've got to 'drive' the system to get it to develop.

It's pretty tough to get a new tank going, without an algae phase. I see it as a necessary developmental phase of all aquariums. As I watched it unfold in my tank, I thought it appeared to be one part of a natural succession. The first colonizers are the bacteria, then cyanobacteria, then micros and finally macros.

One strategy from the fresh water plant folks is to plant a new tank heavily, so when nutrients rise, the plants are already in place, to take them up. I tried this strategy. I still got algae.
Michael, if I had read your post before handing out the macroalgae that I received, I would have followed your hint, of course, of "cutting in three" and planting in three different places ... Too bad I did not! A simple and effective idea ... I put the red ones in more remote places of illumination, but it did not help, they all bleached ...

The microalgae and filamentous do not really worry me ... I fought so much against them before shifting my focus to the planted that did not really bother me. But knowing how to measure nutrients and water quality is an immense challenge!