How to calculate stocking level on a reef tank?

[Luananeko]

I'm still in the early planning stages, but I've pretty much decided my next tank will be a saltwater tank of some sort. I've been doing freshwater tanks for the last 20ish years, so I'm ready for a challenge. I love the look of the various corals, so I'm leaning toward a reef tank... I've gotten my fish wish-list pared down fairly well, but I'm running into some issues trying to figure out what size tank I would need for them all. There seems to be wildly differing ideas on what's a good stocking level, so I'm getting numbers for anywhere between 300 gallons (doable) to 900 gallons (waaaaay not happening). So far I've seen the following ways to calculate stocking:

Method 1 (seems way too general since it doesn't account for activity/swimming level)-
2" of small/medium fish per 10 gallons
1" of big fish per 10 gallons

Method 2 (sounds logical, but gives me about half the required tank size compared to first method, seems too good to be true)-
Group A (Rock dwellers):
Basslets, Pseudochromis, Gobies, Jawfish

Group B (Open swimmers):
Dwarf Angelfish (Centropyge genus), Hawkfish, Firefish, Cardinalfish, Blennies, Chromis, Anthias, Flasher & Fairy Wrasse, Clownfish, Damsels, Six Line Wrasse, Dragonettes

Group C (Large Fish):
Tangs (Naso Tangs count as 3 units), Large Angelfish (count as 3 units), Pufferfish, Triggerfish (count as 3 units), Rabbitfish, Lunar Wrasse, Lionfish, Butterflyfish, Squirrelfish

Rules:
1. (When tank length under 6') Adult size of fish x 10 can't exceed tank length
2. (When tank length under 6') Don't add more than 1 of a genus to aquarium unless same species, compatible as pair, and added at same time.
3. (When tank length under 6') Try to add 2 of group A and 1 of group B per 15 gallons.
4. (For over 6' long tanks) Length + width of tank should be 5 times fish size AND fish size is less than tank width.
5. (For over 6' long tanks) Add members of group C of same genus at same time. Doesn't matter when you add A or B fish.
6. (For over 6' long tanks) 1 unit of fish per 10 gallons. 1 unit = 2 of Group A, or 1 of Group B. 1 Group C fish = 2 units (unless earlier noted to count as 3 units).


Are either of these methods good to follow, or is there a better rule of thumb? How does everyone like to figure their levels?

I have actual stocking compatibility questions too, but I'll leave that for another thread

 

[AquaRick]

I don't think there is any particular "rule" when it comes to stocking. A lot of it depends on so many factors such as current size of fish, future size of fish, filtration used etc.

Why don't you gives us the fish you'd like to keep and we can help you determine what size tank to get. BTW, 300g is a HUGE tank. You'd be able to keep quite a number of fish in that size tank.

 

[Luananeko]

Yep, I know 300g is huge, but considering how my previous plan was to have a 400g Cichlid & Bala Shark tank with 50% water changes weekly, I think a 300-400g reef tank with 10% changes either weekly or every other week is much more manageable

Still playing with numbers and adding/removing species from the wish list as I research more, but here's my "narrowed down" (still large though) list of favorites and their max sizes:

1 - Royal Gramma Basslet - 3"
1 - Yasha White Ray Shrimp Goby w/ Shrimp buddy - 2.5"
1 - Orange Firefish Goby (Nemateleotris magnifica) - 3"
1 - Tiger Watchman Goby (Valenciennea wardii) - 5"
1 - Blue Striped Neon Goby (Gobiosoma oceanops) - 2"
1 - Blue Dot Jawfish (Opistognathus rosenblatti) - 3.5"
1-2 - Clownfish - 3.5" (Either False Percula or True Percula, ideally with an anemone host once I'm sure I could meet the care requirements)
3 - Red Velvet Fairy Wrasse - 4"
3 - McCosker's Flasher Wrasse - 3"
1 - Flame Angel - 4"
1 or school of 5 - Black Axil Chromis (Chromis atripectoralis) - 4"
3 - Stocky Anthias - 7"
6 - Maldives Lyretail Anthias - 5"
1 - Blue Hippo Tang - 1'
1 - Whitespotted Tang (Acanthurus Guttatus) - 1'
1 - Purple Tang - 1'
1 - Indian Black Triggerfish (Melichthys indicus) - 9" (sounds to be one of the very few fish-safe/reef-safe triggers)
1 - Blue Linckia Starfish - 1'

Still researching to check all the compatibilities, but on the surface it sounds like they should work together if added in the correct order. There's also the option of going with two tanks, one reef community and one FOWLR for tangs, anthias, trigger, and a snowflake eel. I'll probably go that route if it doesn't look like this list could work together and/or if they need something bigger than a 400 to handle them all.

 

[carey]

To be honest, in my opinion the list looks fine. You could even add some to it as well is what I was thinking. A 300g plus is a large footprint and the majority of the fish you listed are on the small side. The only fish I have any reservation about is the trigger, I know absolutely nothing about them but they can be a tad nippy. lol My friends have one and it tries to attack my finger out side the glass. hehe

Good luck though and keep the ideas coming. It takes awhile to get to where you want to be as far as the ideal stocking list but half the fun is in the research!

As mentioned above there isn't any formula per say to stocking, it is all dependent on the equipment, your time maintaining it, feeding habits and then down to the actual fish size, temperment and compatibility with the others chosen.

 

[AquaRick]

Wow, that's one mighty list.

I would definitely rethink that trigger. It may work out when it's small, but once it reaches a mature size, it may start weeing your small fish as a snack.

 

[Luananeko]

Awesome! Nice to know I'm not building a list that is doomed from the start, hehe. Normally triggers are very nippy yes, but the Melichthys and Xanthichthys genus ones are thankfully supposed to be MUCH more docile and actually can get bullied by fish half their size

The more I research about Snowflake eels the cooler they sound... Think 1 could work with the rest of that list? It would be stick-fed so it doesn't have the frenzied feeding style that can cause troubles for smaller tankmates, so I think the primary concern would be whether it munched the reef cleaning crew. I plan on having a refugium to help keep the pod, shrimp, and other invertebrate cleaning crew type populations up and so the Anthias have a steady food source, so on paper it sounds like it should work, right?

 

[Luananeko]

Wow, that's one mighty list.

I would definitely rethink that trigger. It may work out when it's small, but once it reaches a mature size, it may start weeing your small fish as a snack.

Yeah, that's one of the aspects I've been trying to research... While the max size is listed as 9" for their wild counterparts, the largest reported captive size is only 4". I think the main one that would be in danger would be the shrimp goby, or maybe the firefish, but if it stays the size folks claim it does in captivity I think it won't bother them... Right? Or is this just wishful thinking? On the WetWebMedia FAQ list there's a case or two where Bob recommends this particular trigger to someone with Firefish, and they're one of the smallest fish on my list...

 

[AquaRick]

I still think that trigger is asking for problems. Humu's are also known to be relatively docile, but I wouldn't put on in with other small fish.

A snowflake eel is iffy too. Some hand fed eels will still go after small fish and some won't. I've seen cases of both situations. It's hit or miss. I don't think I'd chance it, but it's up to you.

 

[Luananeko]

I still think that trigger is asking for problems. Humu's are also known to be relatively docile, but I wouldn't put on in with other small fish.

A snowflake eel is iffy too. Some hand fed eels will still go after small fish and some won't. I've seen cases of both situations. It's hit or miss. I don't think I'd chance it, but it's up to you.

Hmm, good food for thought. Humu's are supposedly much more aggressive than the Melichthys, but at the usual cost of marine fish it's definitely a very expensive "snack" if it gets the taste for fishy flesh... I may end up going with the two tank option after all if that's the case.

 

[Luananeko]

Okay, so if I wanted to go more conservative and go with the 2 tank option instead of one larger tank, would this work better?

200 gallon FOWLR tank:
3 - Stocky Anthias - 7"
6 - Maldives Lyretail Anthias - 5"
1 - Blue Hippo Tang - 1'
1 - Whitespotted Tang (Acanthurus Guttatus) - 1'
1 - Purple Tang - 1'
1 - Magnificent Foxface - 9"
1 - Raccoon Butterflyfish - 8"
1 - Indian Black Triggerfish (Melichthys indicus) - 9"
1 - Humu Picasso Triggerfish (Rhinecanthus aculeatus) - 10"
1 - Snowflake Moray Eel - 2'

200 gallon Reef Tank - Community (or could this be smaller?):
1 - Royal Gramma Basslet - 3"
1 - Yasha White Ray Shrimp Goby - 2.5"
1 - Orange Firefish Goby (Nemateleotris magnifica) - 3"
1 - Tiger Watchman Goby (Valenciennea wardii) - 5"
1 - Blue Striped Neon Goby (Gobiosoma oceanops) - 2"
1 - Blue Dot Jawfish (Opistognathus rosenblatti) - 3.5"
2 - Clownfish - 3.5"
3 - Red Velvet Fairy Wrasse - 4"
3 - McCosker's Flasher Wrasse - 3"
1 - Flame Angel - 4"
5 - Black Axil Chromis (Chromis atripectoralis) - 4" each
1 - White Tail Bristletooth Tang (Ctenochaetus flavicauda)- 6.5"

I'm assuming each would need to have their own sump/refugium still since the FOWLR tank probably would throw off the parameters of the reef if they shared filtration... Or would that not be the case if the sump/refugium was still built to fit a 400g tank?