Det er ik'
svampe men tunikater
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Et shimek citat så kan du selv afgøre om de er gode eller dårlige
They are living on small particulate material in the water, they will rapidly grow (in nature, large masses - and I have seen some colonies that were over 100 feet on a side - can grow at the rate of inches per hour). When they grow at this rate, they really are pulling food from the water. If they do this, and then the total amount of food in the water drops or stabilizes, their population could crash.
This can have two results, and neither is good.
First, it can result in the release of a lot of organic nutrients back into the water, the same as if any other animal died.
Second, it can result in the release of significant amount of toxic chemicals. Tunicates sequester (store) heavy metals and (very nasty) complex organic materials in their tunics as a means of predator defense. When the colonies die (and colonial tunicates are generally not long-lived) these chemicals are released back into the water. If your system has a "significant" die off of these animals, the resulting release of nasty chemicals could be very bad news.
It would be best to stay ahead of the game by harvesting some of the older colonies (don't fragment 'em - that will release toxins, too - just remove the whole colony). If they are spreading, selectively take the older colonies out first (the older ones have more of the chemicals). You can leave some of the newer, rapidly growing colonies. Not only will they be attractive, but by managing their populations in this manner you will be continually removing toxic materials from the tank that would have remained in it, had you not had the tunicates there to concentrate them.
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