Microscopy Thread

[EnterName]

Reef2Reef Microscopy Thread ​

Your tank is packed with life you might have never noticed: rotifers, protists, larval worms, sponges, micro algae, etc. Most of it is smaller than a grain of salt but still absolutely fascinating. This thread is where the Reef2Reef community can take a closer look at what lives "hidden" in our tanks.

Using DIC microscopy, a technique that turns transparent, near-invisible critters into glowing 3D sculptures of light and shadow, I'll be posting high-res images and videos of whatever's crawling, swimming, or drifting through our reef tanks. Everyone is invited to share their microscopy images/videos as well!

No Microscope? No problem. You don't need one to enjoy this thread nor to pursue the hobby. It can be a lot of fun though and help with the proper identification of what you are dealing with.

I hope you enjoy the first few images I have taken for this thread:

1. Amphiprion ocellaris (Common Clownfish) eggs.

(Clownfish egg - Day 1)

(Clownfish egg - Day 5)
It is astonishing how much changes within a few days.​

2. Coral samples

(Briareum sp. polyp with dense zooxanthellae population)
These little orange circles are Symbiodinium sp. (dinoflagellates) living in symbiosis with their host coral to provide energy via photosynthesis in exchange for anorganic molecules and a safe place to stay. Most of you may know them as "zooxanthellae".

(Rhodactis sp. "Rhodactis Plutonium" cnidocytes and some zooxanthellae)
Ever wondered how corals defend themselves? These bean shaped cells are everywhere on corals and will literally shoot a toxin-loaded string (cnidocyst, well visible on the image) into whatever activates them.

(Briareum sp. "sclerite")
Even though Briareum spp. are considered a soft coral they still grow these calcitic spicules that act as a skeleton. These are mainly found in the tissue that is growing on the rocks and holds the polyps in place.
​

3. Various critters

(Some Ostracod I found in the stomach of a flatworm)
Armored crusaceans that you can find sifting through detritus in the substrate. They can look a bit creepy when moving around, but they are beneficial and harmless.

(Juvenile Flatworm. This specimen should be an "Acoel Flatworm". They can be distinguished from "Ghost Flatworms" by their darker coloration caused by their Zooxanthellae. See post #85)
There are thousands of different flatworm species, most of them aren't welcome in a reef tank, but these ones are "ok". Their population can explode and they eat copepods, but at least they don't harm corals, fish, or inverts. This specimen was maybe 1mm in length, but they can grow up to like 4mm.
​

4. Algae and Protists

(Dinoflagellate, probably Ostreopsis sp.)
One of the more dangerous dinoflagellates due to its toxicity according to the identification guide, but finding a few single cells from time to time is absolutely normal and nothing to worry about. I had quite a lot of them for some time, but the toxin never really became an issue. My copperband butterflyfish even ate a lot of them every time I scraped the glass clean. I frequently found them together with diatoms.

(Dinoflagellate, probably Prorocentrum sp., maybe P. lima?)
Another dinoflagellate species I had a lot of for some time. Their numbers grew proportional to the diatom population which might suggest they are preying on diatoms or simply thrive in the same environments.

(Diatom, possibly Licmophora sp.)
These little guys are very abundant in my tank. They attach to pretty much every surface they can find and make up a major portion of the stuff that needs to be scraped off of my tank glass.


Equipment​

Most images are taken with my Leica/Leitz DMRB microscope using DIC microscopy and focus stacking (some are dark-field or simple bright-field microscopy images though). I'm currently using a Sony A7iii to take images in a magnification range from 50x to 1000x.

Posts (ordered by date):
[Photo] Amphidinium (small cell) (Page 1, Post #3)
[Video] Polychaete (Page 1, Post #4)
[Video] Parenchymella larvae of a sponge (Page 1, Post #6)
[Photo] Bubble algae (Page 1, Post #8)
[Photo] Copepod nauplii (Page 1, Post #11)
[Video] Some unidentified "worm" (Page 1, Post #12)
[Photo+Video] Diatoms, likely Nitzschia sp. (Page 1, Post #16)
[Video] Sabellidae or Serpulidae tube-worm (Page 2, Post #24)
[Video] Unknown specimen (Page 2, Post #39)
[Video] Collection of short clips (Page 2, Post #40)
[Video] Unidentified, most likely Trachelocercid ciliate (Page 3, Post #46)
[Video] Spawning Rock Anemone + Gametes (Page 3, Post #50)
[Video] Hydroid Medusa (Page 3, Post #51)
[Video] Cyanobacterium (Spirulina sp.?) (Page 3, Post #52)
[Photo] Branched Halymenia (Halymenia durvillei) (Page 3, Post #60)
[Video] Digitate Hydroid (Page 4, Post #61)
[Photo] Ball Sponges (Tethya sp.?) (Page 4, Post #68)
[Photo] Sea lettuce (Ulva or Ulvaria sp.) (Page 4, Post #69)
[Photo+Video] Hydroid, possibly Obelia sp. (Page 4, Post #80)
[Photo+Video] Spirorbid worm (Page 5, Post #81)
[Photo+Video] Sponge, possibly Clathrina sp. (Page 5, Post #82)
[Photo+Video] Pineapple Sponge, Sycon sp. (Page 5, Post #83)
[Video] Unknown specimen (Page 5, Post #84)
[Photo+Video] Acoel Flatworm (Page 5, Post #85)

Posts (ordered by specimen):

Red & Green Algae
[Photo] Bubble algae (Page 1, Post #8)
[Photo] Branched Halymenia (Halymenia durvillei) (Page 3, Post #60)
[Photo] Sea lettuce (Ulva or Ulvaria sp.) (Page 4, Post #69)

Bacteria
[Video] Cyanobacterium (Spirulina sp.?) (Page 3, Post #52)

Coral samples
[Video] Spawning Rock Anemone + Gametes (Page 3, Post #50)

Diatoms
[Photo] Licmophora sp. (Page 1, Post #1, this very post)
[Photo+Video] Diatoms, likely Nitzschia sp. (Page 1, Post #16)

Dinoflagellates & Protists
[Photo] Prorocentrum sp. & Ostreopsis sp. (Page 1, Post #1, this very post)
[Photo] Amphidinium sp. (small cell) (Page 1, Post #3)

Hydroids
[Video] Hydroid Medusa (Page 3, Post #51)
[Video] Digitate Hydroid (Page 4, Post #61)
[Photo+Video] Hydroid, possibly Obelia sp. (Page 4, Post #80)

Sponges
[Photo] Ball Sponges (Tethya sp.?) (Page 4, Post #68)
[Photo+Video] Root-like growing sponge, possibly Clathrina sp. (Page 5, Post #82)
[Photo+Video] Pineapple Sponge, Sycon sp. (Page 5, Post #83)

Worms
[Photo] Flatworm (Page 5, Post #85)
[Video] Polychaete (Page 1, Post #4)
[Video] Some unidentified "worm" (Page 1, Post #12)
[Video] Sabellidae or Serpulidae tube-worm (Page 2, Post #24)
[Photo+Video] Spirorbid worm (Page 5, Post #81)
[Photo+Video] Acoel Flatworm (Page 5, Post #85)

Other
[Video] Parenchymella larvae of a sponge (Page 1, Post #6)
[Photo] Copepod nauplii (Page 1, Post #11)
[Video] Unknown specimen (Page 2, Post #39)
[Video] Collection of short clips (Page 2, Post #40)
[Video] Unidentified, most likely Trachelocercid ciliate (Page 3, Post #46)
[Video] Unknown specimen (Page 5, Post #84)

 

[Euphyllia97]

Copepod and a sample of green algae during my “uglies” phase. Would love to see some parasites on this topic :)

 

[EnterName]

Amphidinium sp. (small cell)​

Found a small Amphidinium sp. cell. I hope quality improves with new objectives soon, but the small cells will always be a challenge to properly capture.

(Small cell Amphidinium sp. dinoflagellate)
​

Common Name	Dinos / Dinoflagellates / Amphidinium
Classification	Amphidinium sp.
Verdict	Harmful (in large numbers)
Size	≤ 25μm
Found	Substrate, Rockwork, Glass
Rarity	Obligatory (either rare or it takes over)

 

[EnterName]

Polychaete (Unknown genus and species)

(Some polychaete recorded in dark-field)
​

Common Name	Bristle Worm
Classification	Polychaete (genus and species unknown)
Verdict	Depends on genus/species. In this case beneficial
Size	Usually ≤ 5cm (2")
Found	Detritus samples, under rockwork
Rarity	Common

 

[nitrox2000]

The below images are thought to be an Amphidinium species of Dinoflagellates, although not the common variety usually found as it doesn't have a hook like mouth:

The below image is a more common Amphidinium, with a visible hook like mouth:

I have a attached a few videos below on the behaviour and swim patterns:

 

[EnterName]

Sponge larvae / Parenchymella larvae (unknown genus and species)

(Parenchymella larvae of some sponge annoying a little copepod)
​

Common Name	Sponge larvae
Classification	Phylum: Porifera (Unknown genus and species)
Verdict	Depends on genus/species
Size	50μm - 5mm (0.2")
Found	open water column
Rarity	Probably common, but hard to find

 

[Magok]

I smashed a bubble algae (seed bubble?) Between two slides

 

[EnterName]

I smashed a bubble algae (seed bubble?) Between two slides

I liked the idea so I decided to try the same at 400x magnification. The bubble itself has a weird "woven" texture (or messes with DIC microscopy) which I though was really fascinating.

 

[Fish Fan]

Following

 

[BoaConservationist]

alot on my plate this weekend but I may have some contributions to this, will need to fully dive into it , thanks for the invite !

 

[EnterName]

Copepod nauplii (Unknown genus/species)

(Copepod nauplii in DIC)
​

I think there is room for improvement, but still a decent image for identification purposes if someone wonders what is "jumping" around under their microscope :)
These little guys are quite fast and it isn't too easy creating focus stack images of them.

​

Common Name	Copepod nauplii
Classification	Class: Copepoda (genus/species unknown)
Verdict	Beneficial
Size	≤ 500μm
Found	Substrate, Detritus
Rarity	Common

 

[EnterName]

Unknown (Polychaete larvae?)

I wasn't able to fully identify this little guy. It seems to be some annelid. It looks like a Polychaete larvae (or rather a Nectochaete), but the bristles (namely "chaetigers") seem to be missing.
​

Common Name	?
Classification	?
Verdict	?
Size	100μm - 150μm
Found	Detritus sample
Rarity	?

 

[MikeReefs]

Black Bug/Marine Mite on GHA. Not much is known about them but I’ve had them in a LPS tank and no corals were ever harmed. I believe they eat algea and detritus

 

[Hadla]

Love these! I’ve always wanted a decent microscope

 

[EnterName]

Love these! I’ve always wanted a decent microscope

Glad you like the images and videos :)

You don't need an expensive microscope to see/identify the things posted here. You can enjoy the micro-cosmos in your tank (or ponds, puddles, and more) with something between $50 and $200 just fine.

However, you will be limited to bright-field microscopy (background is white/bright and specimens appear flat). Dark-field is affordable, but will already cost a bit more (background is black/dark and specimens appear illuminated like for example the clownfish eggs). If you also want this 3D-Effect where specimens appear to cast a shadow (Differential Interference Contrast), it will get really expensive.

Just start cheap and see if this is something you want to keep doing.

 

[EnterName]

Diatoms (Nitzschia sp.)​

Diatoms are pretty much the first algae most reefers will come into contact with during the "ugly phase". It is commonly confused with dinoflagellates as the symptoms appear similar at first and both frequently appear together. However, diatoms are pretty harmless and easy to control with a bit of patience.

(Diatom bloom on newly introduced dry sand in reef tank)
​

Common Name	Diatoms
Classification	Nitzschia sp.
Verdict	Neutral
Size	≤ 400μm
Found	Substrate, Glass
Rarity	Common (always present in every tank)

Diatoms form a "shell" (called "frustule") out of silicon dioxide [SiO₂] which they get from orthosilicic acid [Si(OH)₄] in the water. You can actually see this shell in the image above (the thin transparent "arms"). Many diatoms can move actively by pushing water through their frustule as you can see in the video below:

(Diatoms moving around and forming aggregates causing brown stains on the substrate)​

They most often bloom in new tanks, but introducing new substrate or using insufficiently deionized RO/DI water for the ATO or during water changes can cause silicates to rise which often leads to a diatom bloom. The treatment is fairly easy: remove the silicate source and wait. Excessive silicates can also be removed with adsorber material if necessary.

(Probably Nitzschia sp. or maybe something like Cylindrotheca closterium?)​

 

[Dom]

1. Amphiprion ocellaris (Common Clownfish) eggs.

(Clownfish egg - Day 1)

(Clownfish egg - Day 5)
It is astonishing how much changes within a few days.

​

These Clownfish egg photos are fascinating. But the story is incomplete.

I would have enjoyed seeing the complete progression.

Thank you for sharing!

Dom

 

[EnterName]

These Clownfish egg photos are fascinating. But the story is incomplete.

I would have enjoyed seeing the complete progression.

Thank you for sharing!

Dom

That's a fair point, unfortunately I can't raise Clownfish babies right now and don't know if I can start another giant project :D

Would be really cool though, and I have been thinking about it a lot... Maybe some day :)

 

[TheMachinistReefer]

I've recently discovered how fascinating this side of the hobby is. I just have a cheap microscope, but it does the job!

 

[EnterName]

I've recently discovered how fascinating this side of the hobby is. I just have a cheap microscope, but it does the job!

Ostreopsis aside, I like the large diatoms. Is it a young tank or did you manage to maintain their population somehow? In my tank diatom diversity has declined over the years and I would really like to understand how to get some of these larger diatoms back.