FAQs on Stocking Large (200+ gallon) Freshwater
Related Articles: Stocking 5, 10 & 20
Gallon Freshwater Aquariums by Neale Monks, Freshwater Livestock by Neale Monks, Freshwater Livestock Selection by Bob
Fenner, The Ethical Aquarist;
Freshwater Fishes to Avoid by Judy Helfrich Acclimation of New Freshwater Livestock by Bob
Fenner, Fishes, Amphibians, Turtles,
Related FAQs: FW
Livestock 1, FW Livestock 2,
FW Livestock 3, FW Stocking 4, FW
Livestocking 5, FW Livestocking
6, FW Livestocking 7,
Systems, & Freshwater
Livestock Selection, Community
New tank; Lg. FW stkg.... chatting.... untenable ideas
I have a new 150 gallon tank. I need some fish that will work
well in here.
I already have a florida gar and an azul peacock bass. Id like this to
be a planted Amazon tank. I was thinking a school of angels until the bass gets
too big to eat them then they will go into my 80 gallon.
<Nah; won't work>
So long term I was thinking
A second gar
<.... not likely another Lepisosteid will get along>
A school of tin foil barbs
My royal clown knife
<Of size might work>
A Severum or two
<Other Cichlids? Possibly>
Stingray? P. Reticulata
<Not likely to live long or well here. Try reading on WWM Re; look for Richard
Ross's book on Potamotrygonids in captivity>
My silver Arowana until my 990 is operational
<Trouble w/ the gar>
Thanks. It is cycled and clear. 15% water changes are done twice a day and are
fed Hikari and frozen
<Keep reading. Bob Fenner>
re: New tank 10/28/15
Perhaps I wasn't clear enough. I need compatible fish for this tank.
<Saw this; and that you hadn't taken the time to read re the
compatibility of the mentioned species on our site....>
I currently have a florida gar and a tochatin azul peacock bass
Both are around 14"
What is one other fish I can put in here?
<.... too many to simply list. Again; the reading, searching.... books.
I have a 11 year old rtc. I was thinking he can go in here.
<Phractocephalus? Not a chance... at this size it will inhale most all else>
He never moves.
<Hunt at night>
He's about 29"
<Swallow most all>
re: New tank 10/28/15
Can his smaller sibling? About 7 years old and 20 inches
<.... you've evidently confused WWM... as a bulletin board. I suggest
you go elsewhere. Perhaps MonsterFishKeepers.com
Re New tank.... Now FW Ray; no data of use or rdg.....
Ok I apologize. I am just an hobbyist lookin for some help.
<No worries... you sound/read like you want to "chat".... go to chat rooms>
If you cant help me with my new tank can you help me with my sick stingray?
<.... have you already reviewed what is archived on WWM? 30k some folks a day
use the site. USE it>
I don't know what happened but he isn't eating. No wounds and less activity.
Water param.s checked out to be perfect. No tankmates except an assassin snail
to keep the pond snails down with the live plants. He is a true hystrix id that
<... see WWM, provide data..... Water quality, foods/feeding, system
150 stocking.... Neale takes over; thank goodness; and him
Stingray is all better. Had a sore on bottom of her disc.
<Glad this ended up well.>
So I ended up with going with a 150 long. Imperial gallons so its a bit bigger.
<Nice size tank.>
Here is what I want to do with it eventually:
1 jaguar cichlid
<Nice, but a hard/alkaline water chemistry fish... different in this regard to
these mostly South American species.>
1 florida gar
<You do realise how big these get? Upwards of 90 cm/3 feet? Not that many
survive that long in captivity. Extremely difficult to keep once they get above
20 cm/8 inches in length.>
1 wolf fish
1 fei feng
8 silver dollars
<Hmm... I wouldn't want to be a Silver Dollar alongside all these giant
And my Pleco collection.
<Nice catfish. Prefers warm, soft, acidic conditions; do ensure you can provide
<Royal Panaque will not tolerate other Loricariidae for long. Even in 150
gallons you'll have to watch them. Adults have been reliably reported killing
1 snowflake eel. Yes I know is a salt water fish but its young and will be in
brackish in a year and full salt within two
<Not how this works. Keep it in brackish from Day 1. Specimens kept in
freshwater "temporarily" usually end up dead. They stop eating eventually, and
by the time the owner has figured out how to set up a brackish system for the
Moray, it's half starved and well on its way to dying. You've got a bazillion
fish in this tank already, only some of which can stay there indefinitely (it's
150 gallons, not 1500 gallons) so why make things even worse for yourself? Or
the fish? I'm guessing you're a teenager by your approach, which isn't a million
miles from my ambitions at college. I kept a tank a bit bigger than this, 200
gallons, and chucked in all sorts of funky stuff. But it didn't always work.
Sometimes a more thoughtful approach to stocking is the hallmark of an elite
fishkeeper, not the range of psycho-killer-giant fish he's keeping. Make sense?>
Temporary residents until they become a problem:↑↓
1 peacock bass. He will be moved later on
1 red tail catfish, will also be moved
<To a pond, I hope. These are massive fish that no-one, sort of Mark Zuckerberg,
has the funds to maintain at home. Truly, these catfish are the aquatic
equivalents of Siberian Tigers. Top predators with no natural enemies thanks to
their giant size. They need massive tanks. Lovely, lovely fish... but don't
encourage the unethical trade in them. 99% of the Red Tails sold end up stressed
or dead. If people didn't buy them, Asian farms wouldn't breed them.>
My now baby gator gar, true alligator.
<Not an aquarium fish. These things are enormous. Why? Why? Don't understand the
point to keeping such things. Cheers, Neale.>
re: 150 stocking 10/31/15
I have a brackish tank cycling but isn't quite finished yet.
<Ah, good, very wise.>
The pond the other things will be moved to is an in house built 3500 imperial
Rtc, Payara, gator and bass will go in there
<Understood. Cheers, Neale.>
re: 150 stocking 10/31/15
I just found out that one of my buddies has just finished cycling his brackish
tank for his scats and archers. So the moray is going there.
My lfs just got some lovely cichlids in, all about 3". I fell in love with a
So here's my plan:
1 x florida gar
1x jaguar cichlid
1x fei feng
1x Payara until he gets too big
1x silver Arowana, until he is big enough for 3500
1x red terror
<Such a random collection hard to be 100% sure, but apart from
predation and some of these being (very) difficult to keep, could work out. Do
watch for signs of aggression, bearing in mind that cichlids may be small
compared to Arowanas, Payara and gar, but they can still cause them to "jump",
damaging themselves in the process. Be aware, and keep the tank
covered. A layer of floating plants would be extremely worthwhile; in giant
tanks/indoor ponds, Water Hyacinth is a good choice. Cheers, Neale.>
re: 150 stocking 10/31/15
Would the plants at the top be for darkness or cover to break the fishes jump?
<Both. Lots of these fish like to "lurk" and floating plants is the easiest way
to do this with really big species. Indian Fern and Amazon Frogbit are my two
favourites. But floating plants also inhibit the jumping reflex. Basically, fish
will jump out of open water but (usually) not through plants because they see
the floating plants as "solid" I suppose. It's a common trick when keeping jumpy
Would duck weed work?
<Can do, but a bit small for your aquarium and likely to clog up filter inlets
and such. See the above suggestions, or visit somewhere like Kew Gardens that
has a big tropical pond. If you have the space, even Water Lilies can work, but
these are fairly demanding, so review their needs thoroughly.>
What fish might be potentially hard to keep out of this mix?
<South American Arowanas have a poor track record in home aquaria compared with
Asian Arowanas. They're bigger and more jumpy. Payara have little to no success
in home aquaria in the long term. Lots of reasons. Easily spooked, especially at
night (jump into glass walls of tank, die). Highly sensitive to water quality,
especially as it ages. Think nitrate and oxygen
levels, not just nitrite and ammonia. Spacious tank, very low stocking levels,
massive filtration, very substantial turnover rates, frequent water changes all
part of the mix -- you're recreating a major river, not a stream, lake or swamp.
I know these fish are widely sold as juveniles, but haven't personally met
anyone maintaining adults, and successful reports online are few. They get to
maybe 8-10 inches quite easily, but then things rapidly become harder, and I'm
sure fewer than 1 in 20 of the ones sold in aquarium shops get anything over 12
inches in home aquaria. Then there's diet. Sure they eat live feeders, but
that's not viable or safe/healthy in the long term. You need plenty of protein
but minimal thiaminase, so shrimps and mussels used sparingly. Don't forget
goldfish and minnows contain thiaminase as well as too much fat, so even if you
bred them at home they'd not be safe. Killifish and livebearers might be a safe
option, but you'd need a bloody FISH FARM to crank out enough of these to
maintain an adult Paraya! So we're back to frozen foods. You need to wean them
onto sufficient quantities of suitable frozen foods, probably vitamin enriched
using your preferred product, while maintaining good water quality. Goes without
saying these fish can kill tankmates up to maybe 2/3rds their size (if such
tankmates have the right shape, anyway) so things like Silver Dollars aren't a
long term option. Hmm.. does this cover my concerns? I hope so. Cheers, Neale>
Compatibility... Lg. sys. FW stkg. 4/22/15
My landlord wants some help regarding my fish. He wants to put them on display
in the office. We have been really good friends for about a decade and he is an
avid monster fish keeper, but he cant put his 7 ft alligator gar in a tank.
He has it in a indoor pond in his basement with tiger shovelnose cats. My
question is, he has a 300 gallon he wants on display with my 20" florida
Shortnose gar, my 7" inch Flowerhorn and a tiger shovel nose catfish. Will this
<Mmm; maybe.... what are the dimensions of this tank? Needs to be three feet or
more wide for the gar.>
We plan to filter it with 3 Fluval fx6 and a sump system. Are these fish
<The FH will likely be eaten in time... by either tankmate>
Never attempted this before.
<Welcome. Bob Fenner>
Re: Compatibility 4/23/15
36" x 36" x 72" = 404 gallons
<Ahh! This will work>
I have access to a 13" Flowerhorn. My gar is 18" and we don't have the tiger
shovelnose yet. Hard to find. Can you recommend a large catfish for my 250
<Mmm; yes. See WWM re Pimelodelids, Doradids; some Pangasiids>
Its a longer model and I want a single specimen catfish tank. Can I keep a tsc
or an rtc in there?
<For a while; few years>
If need be, both have a pond or a different home at a friend use with a 2000
gallon tank. Yes, 2000 gallons. Or are there other catfish that reach about
<Many. Include WWM's coverage of large Loricariids in your reading. Bob Fenner>
Re: Compatibility 4/25/15
So i have a final stocking plan. Will such workout?
1. 1x silver Arowana
<Doesn't do particularly well in home aquaria; I would think carefully about
choosing one of the smaller Asian species if you have the option.>
2. 1x florida Shortnose gar
<Silver Arowana can get very territorial; I would not combine with a Gar.
The risk of damaging either is much too great. Choose one surface dweller, and
3. 1x tigrinus catfish
<A very difficult species to maintain. It's rheophilic, meaning it needs fast,
relatively cool and very oxygen-rich water to do well. There are better choices.
400 gallons is the minimum for this species. How are you going to provide 400
gallons of soft, slightly acidic water? If that's your tap water, great; if not,
be warned this species doesn't thrive in hard water. If you're spending $200 or
more on one of these fantastic fish, you want it to look good, right? Not
skulking around with muted colours because it's stressed!>
4. 1x Green terror
<This doesn't belong.>
5. 1x large mid water fish *can you recommend a suitable specie*
<A Giant Gourami, Pacu, or something along those lines is the usual choice for
use alongside large Pimelodids, Arowanas, etc. But seriously, even with 400
gallons, you'd be sacrificing water quality just to keep one more fish.>
And a large common Pleco
All eat Hikari Massivore and Cichlid Gold pellets with a meaty Monday thing will
salmon, basa fillet, yam, prawn and crayfish completed with in house bred
mollies. For the large fish, I was thinking maybe an Oscar? Or a Flagtail thing?
Not sure what they are called. Silver with a orange and black horizontal banded
This is the 404 gallon.
<Do you have a subscription to the Monster Fishkeepers forum? I think these are
the guys to "chat" to about fish stocking. While a bit liberal with the feeder
fish for my liking, there are some experienced hobbyists there. I have kept both
Silver Arowana and Spotted Gar, and while the latter species was easy in 200
gallons, the Silver Arowana was a challenge. It's a river fish, used to
migrating crazy distances at will, and doesn't really adapt to captivity
particularly well. While researching these, do also dig up some of the older
aquarium books re: jumbo species... "Jurassic Fishes" for example, and "The
Manual of Tank Busters".
re: Compatibility; FW stkg; lg. sys 4/30/15
Here is my final stocking:
1 silver Arowana
1 green terror
4 silver dollars
1 lima shovelnose catfish
1 jack Dempsey
Instead of dollars, could I do red or blue hooks?
<Red-Hook Metynnis may be substituted for Silver Dollars. No idea what Blue
The jack Dempsey is a full grown male and the Arowana is a hand raised baby
re: Compatibility 4/30/15
Hmm. May be just a trade name then. They are grey-ish fish with extended blue
fins. They are schooling. Not sure of scientific name. Do you foresee any
problems with my stocking?
<How big is the tank? Silver Arowana are massive (well over 1 metre long) and
very intolerant of surface-swimmers. Not good aquarium fish really.
Silver Dollars are food items for them. All this, and more, will be on WWM; do
search, perhaps using the term "compatibility" each time.>
Im not sure about the bluegill so I thought I would ask someone with more
knowledge on this than I.
<I have kept Green Sunfish in tropical tanks but no, it isn't ideal. 18-22 C
isn't a problem though.>
I found some really nice pieces of driftwood. How do I make them safe for my new
aquarium? I have poured boiling water on them, sprayed them down a hose and am
currently soaking them, is there anything else I should do?
<This is "found" wood, not store-bought, aquarium-safe "cured" wood? Soak for
some weeks in changes of water. Old school approach: stick in cistern of
lavatory for a few weeks. Otherwise bucket in the garden will do.>
re: Compatibility 5/1/15
The tank is 404 gallons. Ths silver Arowana is about 16-18" long. The full size
of the fish is known and I have plans for it once it reaches a certain size of
We cannot keep Asian Arowanas here as they are illegal.
<Curious. The Asian species are a bit smaller, which makes them nicer in some
ways. Do track down "Jurassic Fishes" if you can... an excellent overview of
Arowanas and various other "ancient" tank busters. An essential read for those
keeping jumbo communities.>
We can only keep south American and African varieties.
<Ah now, the African species is a winner. Cheap and hardy. Grey, to be sure, and
a filter feeder/sand sifter. But a nice fish.>
And the driftwood is some pieces I found along a lake shore.
It doesn't seem to be leaching tannins and it sinks nicely. So just soaking it
will be fine?
<Yes, but will take some time. One bit of wood can usually be added straight to
the tank after a decent clean and a few days' soak. But if you plan on adding a
lot of pieces, soak all the pieces for as long as practical. Use a pH test kit
to keep an eye on the pH after using the bogwood. There's also a chance for
(harmless) fungi to grow on rotting wood, which indicates that the supposed
bogwood you found wasn't fully cured. True aquarium bogwood will have been
"cured" for some months prior to sale.>
I am not quite sure what cistern of lavatory is.
<The big tank of water you flush the water out of. So basically, each time you
flush, the wood gets soaked in new water. Here in the UK, toilet/lavatory
cisterns usually have a lid that lifts off easily, so you can put wood into the
cistern easily. A couple weeks of this may be all you need, because the water is
changed so often.>
re: Compatibility 5/1/15
I have them soaking in a 55gallon trashcan. I change the water daily. How will I
know when it is cured and safe?
<You can't tell _a priori_ but only by measuring the effect they have on the pH
of the water. Put one or two bits in the tank; if the pH stays stable or drops
only slightly over the next few days/couple of weeks, the wood is probably fine.
Add another piece. Test again. Repeat as required.>
I have never seen African varieties for sale around here. Don't know much about
them. Are they predatory? Aggressive?
<Neither to any great extent. Will obviously eat tiny fish, but fine with stuff
too big to swallow whole. They are truly filter feeders, adapted to consuming
plankton and sifting sand for small animals (worms and insect larvae, for
example) and prefer/need copious quantities of such foods (or a suitable
substitute) or tend to starve. Big appetites! Generally pushy but
tolerant of obviously dissimilar fish: Plecs, spiny eels, bichirs, Silver
Dollars and so on. May be troublesome with its own kind though, and probably
other similar fish (Asian Arowana for example). Cichlids will vary, but so long
as the cichlid leaves it alone, the African Arowana won't start any fights.>
They need to be able to hold their own in my tank. Otherwise they would probably
be killed by the Oscar silver Arowana combo.
<Two Arowanas of any kind in one tank is a non-starter for sure.>
Those two are the best of friends, and often go onto each others levels.
They even rest together. Oscar was originally a feeder defect destroyer and then
they saw each other in their own tanks. Inseparable ever since.
What do I do for bacteria on the driftwood?
<Usually not an issue. Wood contains little protein so tends to have little
"rotting" effect or tendency to create bacterial blooms. But as it decays it
releases tannins that lower pH, and if not controlled, this can be dramatic in
soft water situations (less so in hard water). Cheers, Neale.>
re: Compatibility.... chatting 5/3/15
The water around here is hard do the wood was going to be a buffer and decor.
<Unreliable. Hard water (or more specifically, water with high carbonate
hardness) resists pH change downwards rather well. Even in hard water the wood
will release tannins that marked the water significantly, and this can look very
nice. But if you do use wood to "colour" the water a bit, and it might do, use a
pH test kit to keep a track of what happens between water changes. Reducing the
pH without reducing the hardness is unwise, indeed, dangerous. Do review water
chemistry management thoroughly before trying to do so. If your recipe for soft
water doesn't include either collecting rainwater or using an RO filter, well,
you're doing it wrong, so stop. Those are the only two options. Nothing else
works reliably or safely.>
How do I pellet train my baby silver Arowana?
<Get it to associate you with feeding, via live crickets and the like (never
feeder fish), and then try offering a known "carnivore" food when it sees you.
Hikari make some good foods, but you'll find mention of other premium brands at
websites focused on these fish (MonsterFishkeepers.com for example).
Indeed, there are pellet foods designed expressly for Asian Arowanas, including
one from Hikari.>
They bagged him up with a new cichlid I got and so now I have 2 Arowanas.
<Two Arowanas won't cohabit in one relatively small tank. May do so in tropical
ponds... but two is a risky starting point... watch them carefully. Youngsters
are pretty tolerant, but adults can be lethally aggressive. Bear in mind the
ecology of these fish at all times. They are huge, patrol rivers (not streams),
and leap several feet out of the water to catch prey (natives call them "water
monkeys" because they feed on things in trees by leaping out of the water).
Aquarium fish? Nope. Plan ahead. Carefully.>
He is about 4 inches. Is he too young?
<Possibly, if the other Arowana is substantially bigger. They do bully weaker
specimens. Do also bear in mind very young specimens (with yolk sacs still
attached) are extremely sensitive and have a poor track record for surviving
stress. The ideal size for new specimens is around 15-20 cm.
New setup ideas... FW stkg., lg. sys.
Hello, this is my first time writing and I have a few questions.
In the next couple of months I plan to build a plywood aquarium
(96x24x72) and am wondering if the fish I am planning
would be compatible. Dovii female with Managuense male (or vice
versa), Tiger shovelnose, Female Festae, Sailfin Pleco and a Indo
Datnoides. Nothing is written in stone, so any other
suggestions would help. Thanks.
<These fish species can live together in such (a large) volume. The
cichlids need to be started near the same size (not large adults) and
the Pimelodid cat not too big (lest it swallow them); and you may have a
hard time feeding the Siamese Tiger Fish with such boisterous
companions. Bob Fenner>
New ideas cont.; canister filters/filtration 8/17/13
I forgot to mention I gave a ocean clear (forgot the model #, not in
front of me) & a Nu-clear 530. Thanks again.
<Mmm, I would use other than cartridge filters on a large aquarium (too
much maintenance, electrical/pumping expense). DO see (read) on WWM re
filtering a big system. Bob Fenner>
Re: New ideas cont., lg. FW stkg.
Thanks Mr. Fenner, I'll check it out. Have a nice week.
<You too MK. B>
Re: New setup ideas 8/19/13
Thanks again Mr. Fenner, should I grow the cichlids out before I add the
<If the Catfish is more than a few inches in length, yes! This large
Pimelodid can/will try to inhale most all animals that will fit in its
capacious maw/mouth. B>
Re: New setup ideas 8/19/13
One more thing, which would be better a female Dovii and male Managuense
or female Managuense and male Dovii?
<Hard to sex when young, but may try to interbreed... Males are
"prettier", more interesting behaviorally to most folks, but more likely
New tank build. FW stkg. lg. sys.
I am currently in the process of starting up my fish tanks again. My
original plan was to build a "fish tank wall" in my basement, utilizing
the 3 55gal and 1 bow front 75gal, creating a wall of tanks. However, as
I get further into this I am thinking of actually doing one large tank.
Selling the rest (except the bow front).
Using the current base I have built would allow me a tank about 144" x
21" and any height really, but for structural reasons, probably about
Which, if my math is correct, gives about 270gallons. I design and build
boats so the actual build, (plywood sandwich fiberglass with 3/8" 4'
glass windows in front probably) isn't really an issue.
However, I really don't know what to put in it. I'd love rays, but the
base size isn't anywhere near big enough and doubt I could financially
support them. I would like another salt water tank, but start up costs
be crazy, so I've decided on tropical. I really like Bala sharks, I've
owned them before but unfortunately they outgrew the 75gal and I
couldn't keep them. Would this tank work for 4 or 5 bala's?
Could I put anything else in there with them?
<I'd go w/ a S.E. Asian theme... stocking larger Barbs, Danios, Loaches
(my fave, Clowns)... and more!>
Mine weren't that aggressive but I've heard they can be.
If Bala sharks will work, what sort of environment would they really
<Broken decor to mid height, the top open for swimming, w/ perhaps some
floating plants (Ceratopteris...)>
I can make it high current flow or low. I had thought of using real rocks
along the back wall. If Bala sharks aren't really suited, any
suggestions on alternatives?
<Many... I'd consider a Discus, or Angelfish centered habitat,
Australian et al. Rainbowfishes, any of several types of African
Any advise <advice> would be greatly appreciated. Since I'm building
this from scratch I'd rather build it to suit the fish than find fish to
<I'd shoot for a 24" height... more symmetrical w/ length, and just as
easy to build, install... more decorative possibilities. Bob Fenner>
Adding fish to my aquarium
your site has helped me before, it is very informative. I have a couple
questions about adding new fish to my current set up.
I have a 125 gallon 6 foot long aquarium. I have 4/ 300 watt
<Mmm, I'd remove two of these>
3/ Marineland 350 penguin Biowheel filters and 1/ 350 Odyssea canister
filter. 2/ air pumps...I do weekly water changes of 20%..Once a month I
do a 50% water change. I alternate cleaning the filters one per
The temp is on 82F all levels of ammonia/nitrates/Nitrites are 0. I
have had this aquarium for 6 years I bought all my fish when they where
very small. For the first 4 years the PH was 7.0, but since I lived in
this house the past two years the PH has been 8,0.
<I wonder what happened to elevate the pH a full point (ten
All my fish have adjusted to the change and are doing very well. I
don't fight with the PH level because it is consistent and the fish
are doing fine.
I know my fish are larger now, but by the end of this year I am getting
a 300 gallon. ( I am waiting on my husband to install plumbing so it
would be easier for water changes) The fish I have are...2/ 8"
gold Severums, 1/ 8" green Severum, 1/12" iridescent
<Will get much, make that MUCH larger>
2/ 5" blood parrot fish, 2/ 4" Bala sharks,
<Unusual that these have not grown more>
1/ 9" common Pleco, 1/ 4" silver dollar, 1/ 4" angel
fish, 1/ 4" clown loach,
<Social animals... perhaps you can grow up a few others in your
3/ 3" fire-mouths, 5/ 2" jelly bean parrot/convict mix, All
my fish get along great and have for the last 6 tears. They have plenty
of hide outs to claim for them selves.
My questions are..Is there a better filter system I could use?
<Mmm, yes... for the 300, I'd switch to something in the way of
See WWM re... for the present tank, the 125, there are better canister
filter brands... My fave is Eheim>
Are the silver dollar and clown loach fine by them selves of should I
get a couple more of each?
<Better with more... though the "dollars" might bicker
quite a bit at first>
With this set up, the fish and the fact I am going to a 300 gallon by
the end of the year, could I add a baby frontosa to this mix?
<Perhaps one of a few inches (3-4) length>
I understand they need a high PH, but I am not sure if my PH 8.0 would
be ok for them and my other concern is the compatibility of my existing
They are very calm and get along very well.
<I do think you'd be fine with this/these additions>