My newest creation, the Daggertooth Fish! https://www.dndbeyond.com/monsters/43019-daggertooth-fish

Ver 1.2: https://www.dndbeyond.com/monsters/44847-daggertooth-fish

A walking speed of 10 to 20 feet is more appropriate for a fish out of water. Do include the fact that it can breathe water and that it can stay out of water for thirty minutes before it needs to worry about suffocating in the traits section.

Thanks for the feedback. My reasoning for the high land speed was to make them both thematically and mechanically dangerous. I want PCs terrified when these "fish" suddenly splash out of the water and literally race towards them.

I thought I had included the air breathing, but I will go back and edit.

I think it's waaayyy to nasty for it's CR 1/2.  Especially in a pack.

For it's CR it

• hit on the upper end of that range (+7 instead of +5)  Based on it's CR + Str, it should be hitting on a +4.  (55% chance to hit PLATE)
• Deals 1d8 damage which is pretty normal for single attack creatures, but also deal poison damage... so you're talking about an average of 14 damage per hit.
• The poison also does 1d4 rounds of Paralysis... That mean 1 failed save and all attack rolls have Adv (+75% chance to hit plate) AND auto Critical, so you're now dealing an average of 21 damage per hit.
• It is stupid fast, if you want to keep it "fast" make it's speed 10, with the Bonus Action it can still "motor" 20 or 30 feet!
• It's Hit Dice are average for Large Beasts of it's category, but not Tiny ones.
• This sentance makes zero sense.  " Though outrunning them may not be possible, it may also be the only real defense against an entire pack of them."  Either it's possible or it's the only defense..  it can't be both.

Also you said they take 7 (1d8) Poison, so I assume you meant 7 (2d8) Poison.

The problem is they are too fast, in a bad situation the PC's CAN'T run away, because these monsters can move 80' and STILL attack.  That means short of being mounted on horses the PCs will never be able to flee.  Even if they are mounted a horse moves 60, 60 * 2 (Dash) is 120 ft.  These things move 40ft, so 40*3 (Move, Dash, Aggressive), means they can STAY inside 5ft of a horse and take the AoO as it tries to flee...

I'd say don't let them breath air.  Give them "Hold Breath" for 15 minutes.  This will make them a terrifying prospect, but something that *has* to stay near water.

Also, why is it resistant to Cold and Immune to Poison?  Most Beasts that have poison aren't immune to poison, even their own.  Why Cold?  Does it live in an arctic climate?  Most fish are cold blooded, the exception of some high end predators who are warm blooded to have more bursts of speed.

Also, I'd recommend having their eyes bio-luminescent blue.  In water red wave lengths are *quickly* absorbed, that is why most deep sea animal emit blue light.  Most deep sea creatures can't actually SEE red light, because they didn't evolve the cells to see red light as there is so little of it down there.  There are a *few* that emit red light and can see red light, but these are terrifying predators that do so because most fish can't see them, but they can see their prey.  (Think night vision googles).

Social Structure makes no sense.  Are these amphibious parana or are these Jurassic Park intelligent veliraptors?  You have them as Int 1, but then say "These hunters tend to attack in packs of 4 to 10 individuals. One Daggerfish will slowly swim towards prey, lulling them into a false sense of security, and then suddenly the entire pack will swim forward at lighting speed from all sides, surrounding the target in a whirlwind of snapping teeth."  Are they the kind of creature that is a "carnivorous eating machines" with low intelligence or is an intelligent and coordinated hunter?  The first would unlikely work in groups.

Thanks for all the feedback, FMB. I will make some updates!

I have updated with some of the feedback from FullMetalBunny.

https://www.dndbeyond.com/monsters/44847-daggertooth-fish

mjsoctober,

I like it.  This is definitely something I think a Druid think about turning into at it's CR, but not hands down the best thing.

I like your choice for 15' movement.  With the Aggressive trait, means a human commoner can't escape using the Disengage action, because the Daggerfish can move 30' and still attack.  This makes it nasty burst as an ambush predator, as 30ft from water is still inside attack range.  That said, if the commoner takes the AoO and Dashes and the Daggerfish doesn't kill/paralyze them... the commoner can out run the daggerfish.  It makes it fit your fluff really well, it  is scary and hard thing to flee, but not impossible.

The upping of Int makes it make sense as a pack hunter.

One question you may or may not want to add into psychology is how do Daggerfish handle taking down prey.  Once they have downed prey (paralysis) will they ignore it and keep searching out more food, or will they ignore others to focus on protecting/eating their kill?

If they focus on their downed prey it means they are more likely to kill a PC, but the party has to make the hard decision if they should cut and run because they are already dead.

I would see them as wanting to maximize their eating potential. The more prey they can take down, the better, but not if it means risking running out of breath on land. I would imagine the usually like to pick off lone prey or stragglers, especially close to water, and then as a group drag the prey into the water?