Colonial hydroids

[KING KONG]

So I wanted to know that why everyone hate colonial hydroids? Do they really do that much damage? I have them from almost 5 yrs and I didn't noticed any harm they caused so I let them be there. Here is a vedio.

 

[EeyoreIsMySpiritAnimal]

There are many different types of colonial hydroids and some stay in one place without spreading and causing problems.

There are also many types of aiptasia anemones and some stay in one place without spreading...

The fact that problematic colonial hydroids are commonly found in hobbyists tanks is the reason most "hate" them and recommend removal as soon as they appear; same with Aiptasia.

 

[KING KONG]

There are many different types of colonial hydroids and some stay in one place without spreading and causing problems.

There are also many types of aiptasia anemones and some stay in one place without spreading...

The fact that problematic colonial hydroids are commonly found in hobbyists tanks is the reason most "hate" them and recommend removal as soon as they appear; same with Aiptasia.

Mine are spread all over the tank. I see many of them floating (offsprings). How can we identify bad ones? As I have found nothing about them on internet

 

[EeyoreIsMySpiritAnimal]

Mine are spread all over the tank. I see many of them floating (offsprings). How can we identify bad ones? As I have found nothing about them on internet

Hydroids sting other things in the tank - coral, fish, you (if you touch them and are sensitive to the nematocysts). So the "bad ones" are the ones that spread throughout a tank and are able to irritate other inhabitants, especially sessile things like coral.

If you personally aren't having any problem from them in your tank, great. But please do warn anyone you sell/give coral or rock to that you have hydroids. I bought a coral rock from a local hobby group's vice president that he knew had hydroids (but didn't think it was important to tell me) and I had to completely break down the tank it was in. Luckily it was a small "temporary" tank, but I ended up losing a decent amount of coral.

 

[KING KONG]

Hydroids sting other things in the tank - coral, fish, you (if you touch them and are sensitive to the nematocysts). So the "bad ones" are the ones that spread throughout a tank and are able to irritate other inhabitants, especially sessile things like coral.

If you personally aren't having any problem from them in your tank, great. But please do warn anyone you sell/give coral or rock to that you have hydroids. I bought a coral rock from a local hobby group's vice president that he knew had hydroids (but didn't think it was important to tell me) and I had to completely break down the tank it was in. Luckily it was a small "temporary" tank, but I ended up losing a decent amount of coral.

Then mine are good ones. They are also on glasses and I had touched them and they didn't sting me so I think I am lucky

 

[EeyoreIsMySpiritAnimal]

From: https://www.britannica.com/animal/Liriope

"hydroid, any member of the invertebrate class Hydrozoa (phylum Cnidaria). Most hydroids inhabit marine environments, but some have invaded freshwater habitats. Hydroids may be either solitary or colonial, and there are about 3,700 known species."

 

[EeyoreIsMySpiritAnimal]

Then mine are good ones. They are also on glasses and I had touched them and they didn't sting me so I think I am lucky

You may be lucky that you're not sensitive to their nematocysts, but that doesn't mean they are "good ones". What makes them "good" or "bad" is whether they are isolated to one area or if they spread.

Again, if your coral, etc, aren't bothered by them, that's great, but you asked why people "hate" them, and the fact that they can take over a tank is a primary reason.