Upgrade Aquatic is a Minecraft mod by Team Abnormals that fills the oceans, rivers and swamps with new mobs, plants and blocks. It adds Thrashers and Great Thrashers to the frozen oceans, Nautiluses to the warmer seas, Pike and Perch to rivers and swamps, and three kinds of Jellyfish, along with Mulberries, Driftwood, new corals and four new potions.
It’s a vanilla style mod, so nothing in it feels out of place, and a lot of it is small quality of life stuff you’ll only notice once you’re playing. This guide covers the things people actually go looking for, which is mostly the Elder Eye, the Thrashers and what their teeth are good for, and then the rest of the mod after that.
The version this guide covers is Upgrade Aquatic 6.0.3 for Minecraft 1.20.1, which runs on Forge and NeoForge and needs the Blueprint library installed alongside it. Older versions for 1.16.5 and 1.19.2 have most of the same content, but some of the numbers and a few recipes are different, so check your version if something doesn’t match up.
What Upgrade Aquatic Adds
Most of what Upgrade Aquatic adds is spread out across the water biomes, so where you find something depends a lot on the temperature of the ocean you’re in. The cold and frozen oceans have the dangerous stuff, the warm oceans have the colorful fish and Jellyfish, and the rivers and swamps get their own freshwater fish and plants.
| Mob | Where It Spawns | Hostile? | Why You’d Want It |
|---|---|---|---|
| Thrasher | Cold, Deep Cold and Frozen Oceans, below Y 30 | Yes, in water | Thrasher Teeth for Tridents |
| Great Thrasher | Deep Frozen Oceans, a quarter of Thrasher spawns | Yes, in water | More Teeth and Music Disc fragments |
| Nautilus | Oceans, Deep Oceans, Warm and Lukewarm Oceans, below Y 30 | No, it swims away | Nautilus Shells |
| Pike | Rivers and Swamps | Only to other fish | Food, and it collects items |
| Perch | Swamps | No | Food and Fisherman trades |
| Lionfish | Warm Oceans | Poisons whatever it touches | Repellence potions |
| Box, Cassiopea and Immortal Jellyfish | Warm and Lukewarm Oceans | Box Jellyfish can sting | Jelly Torches |
| Flare | Only by converting a Phantom | Yes | Phantom Membrane |
On top of the mobs, the mod adds new corals, Driftwood that washes up on beaches, River Trees with Mulberry Vines hanging off them, Beachgrass, Pickerelweed, Searockets and Flowering Rush. There’s also a lot of building blocks, like Kelpy Cobblestone, Coralstone, Scute Shingles and Tooth Bricks, which are mainly there for builders and aren’t covered in much detail here.
The Elder Eye
The Elder Eye is the most searched for thing in Upgrade Aquatic, and it’s one of the more useful blocks in the mod once you know what it does. It’s a small eye block that works like a motion sensor for redstone, so it watches in a straight line in front of it and gives off a signal when something walks into its view.
The only way to get an 
Elder Eye is from an Elder Guardian, which always drops exactly one when it dies. There’s no recipe for it and no other source, so you’ll need to take on an Ocean Monument if you want one, and since there are three Elder Guardians in every monument, one raid gets you three Elder Eyes.
Elder Guardian Extra Drop
Elder Eye Once it’s placed, the Elder Eye faces towards you and looks out for up to 15 blocks in that direction. When a mob or player moves into its line of sight it outputs a redstone signal, and that signal gets stronger the closer the mob is, so something right in front of it gives full strength 15 and something at the edge of its range gives a strength of 1.
The line of sight stops at the first solid block, so a wall two blocks in front of the Elder Eye cuts its range down to one block. It checks a few times every second, which makes it quick enough to open a door as someone walks up to it, and it can be placed underwater too, since it’s waterloggable.
Right-clicking the Elder Eye closes it, which turns it off and stops it giving any signal at all. Right-clicking it again opens it back up. That makes it easy to switch a hidden door or a mob trap on and off without breaking anything, which is handy if you only want it active some of the time.
Common uses for the Elder Eye are automatic doors, alarms for a base entrance, and detecting when mobs reach a certain point on a mob farm. Because the signal strength depends on distance, you can also use a Comparator style setup to do different things depending on how close a mob is, although most people just use it as a simple on and off sensor.
Thrashers and Great Thrashers
Thrashers are the main threat in Upgrade Aquatic. They’re big, blind, shark like mobs that live in the cold oceans and hunt by sound, and they’re the reason a lot of people install the mod in the first place, since they make the frozen oceans a lot more dangerous than they are in vanilla Minecraft.
A Thrasher spawns in Cold Oceans, Deep Cold Oceans, Frozen Oceans and Deep Frozen Oceans, but only below Y 30, so you won’t see them near the surface unless something draws them up. They can spawn during the day, but less often than at night. In Deep Frozen Oceans, a quarter of the Thrashers that spawn come out as a Great Thrasher instead.
| Thrasher | Great Thrasher | |
|---|---|---|
| Health | 50 | 125 |
| Attack Damage | 5 | 8 |
| Armor | 8 | 16 |
| Where | Cold, Deep Cold, Frozen and Deep Frozen Oceans | Deep Frozen Oceans only |
| Drops | Thrasher Teeth | Thrasher Teeth and Disc Fragments |
Thrashers can’t see, so they only go after you while you’re in the water. If you’re standing on land, on a boat or on the ice, a Thrasher won’t target you, even if you’re right next to it. They use a sonar pulse to find things, and hitting one from further than 8 blocks away just makes it swim over to where the hit came from.
When a Thrasher does catch you, it grabs you in its mouth and thrashes you around, which is where the name comes from. The way out is to keep hitting it, since enough hits from close range will stun it for a moment. Harder hits stun it faster, and on higher difficulties it takes more hits before it gets stunned, so a strong weapon really matters here.
If a Thrasher ends up on land it’ll flop about like a fish, and after two minutes out of the water it starts to dry out and take damage. That makes drawing one into shallow water or up onto land a decent way to fight them, since it can’t target you on land and it slowly dries out the longer it stays there.
Thrasher Drops
Thrasher Tooth Thrasher Tooth The Great Thrasher is the tougher version, with two and a half times the health and double the armor. It isn’t a boss and it doesn’t have a health bar, but it’s still the hardest fight in the mod, so it’s worth bringing a Trident or a good sword with Impaling and some Water Breathing before you go looking for one in a Deep Frozen Ocean.
Great Thrasher Drops
Thrasher Tooth Thrasher Tooth 
Disc Fragment Looting helps with both Thrashers, since it raises the chance of the extra Tooth by 20% per level and adds to the Disc Fragments from a Great Thrasher. A Looting III sword turns most Thrasher kills into two Teeth, which cuts the number of Thrashers you need for each Trident down a lot.
Thrasher Teeth, Tridents and the Music Disc
Thrasher Teeth are the reason to hunt Thrashers, because Upgrade Aquatic uses them to make Tridents craftable. In vanilla Minecraft the only way to get a Trident is to kill Drowned and hope for a lucky drop, so a recipe for them is a big deal if you want a Trident with the enchantments of your choice.
| Item | Recipe | Makes |
|---|---|---|
| Prismarine Rod | 2 Prismarine Shards placed diagonally | 1 Prismarine Rod |
| Trident | 3 Thrasher Teeth in the top right corner, 2 Prismarine Rods along the diagonal | 1 Trident |
A 
Trident takes three Thrasher Teeth and two 
Prismarine Rods, and each Prismarine Rod is made from two 
Prismarine Shards. So you need at least three Thrasher kills per Trident, and a lot fewer if you’re using a Looting sword. Once you’ve got the Trident it’s a normal vanilla one, so it takes Loyalty, Riptide, Channeling and Impaling like any other.
There are a few other uses for Thrasher Teeth once you’ve got enough Tridents. Nine of them make a 
Tooth Block, which can be turned into Tooth Bricks and Tooth Tiles for building, and two of them with some 
Prismarine Crystals make a 
Tooth Lantern. One Thrasher Tooth also crafts into six Bone Meal, which is a good trade if you’ve got too many.
Clerics also buy Thrasher Teeth once they reach Expert level, paying one Emerald for each one, and Masons sell Tooth Bricks and Tooth Tiles at Master level. The Cleric trade is a nice way to turn spare Teeth into Emeralds, although you’ll probably want to keep a few for another Trident or two before you sell them off.
The Disc Fragments that Great Thrashers drop are for the mod’s only 
Music Disc, which plays Atlantis by hatsondogs. Nine Disc Fragments in a crafting table make the Music Disc, and since each Great Thrasher only has a one in three chance of dropping up to three of them, it usually takes a few Great Thrasher kills to finish it.
The Music Disc works in a Jukebox like any vanilla disc, and it’s a nice trophy to have in an ocean base. Keep any spare Disc Fragments you get after the first one, as there’s no other use for them and they stack, so a second disc only needs a few more Great Thrasher kills.
Nautiluses
The Nautilus is a small passive mob that lives in the Ocean, Deep Ocean, Warm Ocean and Lukewarm Ocean biomes, below Y 30. It’s got 18 health and it doesn’t fight back, and when you hurt one it swims away quickly instead, so you’ll often have to chase them down if you want the shells.
Killing a Nautilus gives you up to one 
Nautilus Shell, and Looting can add another. In vanilla, Nautilus Shells only come from fishing, from Drowned holding them and from the Wandering Trader, so the Nautilus gives you a much easier way to collect the eight you need for a 
Conduit.
Nautilus Drops
Nautilus Shell There’s one more way to get Nautilus Shells, which is 
Embedded Ammonite. It’s a block that generates in stone on beaches, stony shores and in oceans, and smelting it in a Furnace or Blast Furnace gives you a Nautilus Shell. It’s easy to miss when you’re mining, but it’s worth grabbing any you see.
You can also catch a Nautilus in a 
Bucket like a vanilla fish, which gives you a Bucket of Nautilus. That’s mostly useful for moving them into an aquarium or a build, since a Nautilus you’ve moved into your own tank is a lot easier to find again than one out in the open ocean.
Pike, Perch and Lionfish
Upgrade Aquatic adds three new fish, and each of them lives somewhere different. Pike are found in Rivers and Swamps, Perch are only found in Swamps, and Lionfish are only found in Warm Oceans. They can all be caught with a Fishing Rod in those same biomes, as well as killed or picked up in a Bucket.
The Pike is the most interesting of the three. It’s a predator that hunts smaller fish, and it’ll swim over and pick up items it finds in the water and carry them around in its mouth. They like to hide in Pickerelweed, and there are a lot of different Pike patterns to collect, which is what the collect all the Pike advancement is about.
The Lionfish is pretty but dangerous. It poisons anything that touches it, including you, so it’s best to catch one with a Bucket or kill it from a distance. Lionfish are also the ingredient for the Potion of Repellence, which is covered further down in this guide, so it’s worth grabbing a few when you find them.
All three fish can be cooked in a Furnace, Smoker or on a Campfire, just like vanilla fish. 
Cooked Pike, 
Cooked Perch and 
Cooked Lionfish are all decent food, and the Fisherman villager has trades for all three of them if you’d rather trade your catch for Emeralds.
If you’d rather sell your fish, the Fisherman villager gets a few new trades for them. Some of them turn raw fish into cooked fish for a single Emerald, which saves you the fuel, and the others buy raw fish outright, which is a steady Emerald source if you’re fishing a lot.
| Fisherman Level | Trade |
|---|---|
| Apprentice | 6 Raw Perch and 1 Emerald for 6 Cooked Perch |
| Journeyman | Buys 14 Raw Perch for 1 Emerald, or cooks 6 Raw Pike for 1 Emerald |
| Expert | Buys 5 Raw Pike for 1 Emerald, or cooks 6 Raw Lionfish for 1 Emerald |
| Master | Buys 3 Raw Lionfish for 1 Emerald |
These trades sit alongside the normal Fisherman ones, so a Fisherman won’t offer all of them at once. They’re a nice extra for anyone building near a swamp or river, since Perch and Pike are easy to catch in large numbers with an auto fishing setup.
Jellyfish and Jelly Torches
There are three Jellyfish in Upgrade Aquatic, the Box Jellyfish, the Cassiopea Jellyfish and the Immortal Jellyfish. They all live in Warm and Lukewarm Oceans and they come in a bunch of different colors, which is what decides the color of their Jelly Torches. They’re mostly harmless, apart from the Box Jellyfish, which hunts fish and will sting you if you get too close.
A sting from a Box Jellyfish gives you Poison II for 30 seconds, which hurts a lot more than it sounds like it should. The Cassiopea Jellyfish spends most of its time upside down on the sea floor, hiding in seagrass, and the Immortal Jellyfish just drifts around and is the easiest of the three to catch.
The main reason to find Jellyfish is Jelly Torches. Right-clicking a Jellyfish with a Prismarine Rod uses up the Rod and gives you a Jelly Torch in that Jellyfish’s color. Afterwards the Jellyfish will sometimes need a break, of between 15 and 30 seconds, before it can give you another Jelly Torch.
Jelly Torches work underwater, which is the whole point of them, and they come in eight colors to match the Jellyfish. You can also scoop a Jellyfish up in a Bucket, which is the easiest way to bring a few back home so you can keep making Jelly Torches without having to go back to a Warm Ocean every time.
Mulberries
Mulberries grow on Mulberry Vines, which hang off the River Trees that Upgrade Aquatic adds along riverbanks. The vines grow over time, and once they’re ripe you can right-click them to pick the berries, which resets the vine so it can grow some more. Double vines give you two 
Mulberries at a time instead of one.
A Mulberry can also be planted to grow your own Mulberry Vine, so you don’t have to keep going back to the river once you’ve got a few. Farmers sell five Mulberries for one Emerald at Apprentice level, which is the easiest way to get started if you can’t find any River Trees nearby.
There are three foods you can make from Mulberries. A 
Mulberry Jam Bottle takes a Mulberry, some Sugar and a Glass Bottle, 
Mulberry Bread takes a jam bottle and a loaf of Bread, and a 
Mulberry Pie takes a Mulberry, Sugar and an Egg. You can also store jam as a Mulberry Jam Block, and turn the block back into jam bottles later.
Mulberry Bread fills the most hunger of the three, while Mulberry Pie keeps you full for longer, so both are worth making. Mulberries can also be crafted into Magenta Dye, which is handy if you’ve got more of them than you know what to do with and need some dye for a build.
Upgrade Aquatic Potions
Upgrade Aquatic adds four new potions, and they’re brewed in a normal 
Brewing Stand starting from an Awkward Potion. Two of them are about sleep and Phantoms, and the other two give you a sort of aura that affects anything touching you, which is a lot more useful than it sounds.
| Potion | Brew It From | What It Does |
|---|---|---|
| Restfulness | Awkward Potion + Cocoa Beans | Takes one day off your time since last rest (two with Restfulness II), and kills Phantoms instantly |
| Insomnia | Restfulness + Fermented Spider Eye | Adds a day to your time since last rest, and turns a Phantom into a Flare |
| Repellence | Awkward Potion + Raw Lionfish | Anything touching you gets Poison II, for 3 minutes (8 with Redstone) |
| Vibing | Repellence + Fermented Spider Eye | Anything touching you gets Regeneration II, for 3 minutes (8 with Redstone) |
Restfulness is the one most people will use, since it stops Phantoms from spawning without having to sleep, which is great on servers where not everyone goes to bed. Insomnia does the opposite, and throwing it at a Phantom turns it into a Flare, which is a Phantom variant that drops Phantom Membrane when a player kills it.
Repellence is good for keeping mobs off you, since anything that bumps into you gets poisoned. Vibing gives Regeneration to anything that touches you instead, so it’s more of a team potion, and it’s handy for healing pets or other players who stand right next to you during a fight.
Bedrolls and Other Changes
A 
Bedroll is a bed that doesn’t set your spawn point, which makes it perfect for sleeping through the night while you’re out exploring, without moving your respawn away from home. It’s made from Leather and White Wool, and it can be dyed any color, or bought from a Leatherworker for one Emerald.
Bedrolls can also be placed underwater, and sleeping in one underwater gets you an advancement. It’s a small thing, but it means you can skip the night even while you’re working on an ocean build, which is handy since beds can’t normally be placed in water.
There are a few changes to vanilla as well, most of which can be turned off in the config. A 
Turtle Shell now gives you Water Breathing for as long as your head is underwater, but it loses durability while it does, one point every two seconds. Squid ink gives nearby mobs Blindness, and Glow Squid ink gives Night Vision instead.
You can also build with a lot of new blocks from the ocean. 
Luminous Prismarine is a glowing Prismarine made with a Glow Ink Sac, Driftwood washes up on beaches in Driftwood Logs, and every coral color has its own Coralstone, with stairs, slabs, walls and a chiseled version for builders.
Tips for Upgrade Aquatic
Grab the Elder Eyes from every Ocean Monument you clear, since there’s no other way to get them. Three per monument sounds like a lot, but once you start using them for doors and farms you’ll run out quicker than you expect, and going back to find another monument is a lot more work than just keeping them.
Fight Thrashers from a boat or from the ice if you can. They can’t target you when you’re out of the water, so standing on the edge of a hole in the ice and hitting them as they come up is a lot safer than swimming down to them, especially if a Great Thrasher is around.
Keep some Prismarine Rods on you when you head to a Warm Ocean. Jellyfish are the only source of Jelly Torches, and having a stack of Rods means you can grab a bunch of torches in one trip, rather than having to go back and forth between the ocean and your crafting table every time you run out.
Brew a few Restfulness potions early on if you’re on a server where people don’t sleep. Phantoms are a real pain on multiplayer, and each Restfulness potion takes a whole day off your own counter, so drinking one every few nights keeps Phantoms away without you ever having to find a bed.
Upgrade Aquatic FAQ
The Elder Eye only drops from Elder Guardians, which always drop exactly one when they die. There’s no recipe for it, so you’ll need to clear an Ocean Monument, and since each monument has three Elder Guardians you can get three Elder Eyes from one raid.
The Elder Eye is a redstone sensor that watches up to 15 blocks in front of it. When a mob or player moves into its line of sight it gives off a redstone signal, which is stronger the closer the mob is. Right-clicking it turns it off, and right-clicking it again turns it back on.
Put three Thrasher Teeth in the top right corner of a crafting table and two Prismarine Rods along the diagonal. Prismarine Rods are made from two Prismarine Shards, and Thrasher Teeth drop from Thrashers, which live in the cold and frozen oceans below Y 30.
Great Thrashers only spawn in Deep Frozen Oceans, where a quarter of the Thrashers that spawn come out as a Great Thrasher. They spawn below Y 30, so you’ll usually need to dive or wait near the bottom to find one, and they only attack you while you’re in the water.
