The party observes Fish #A shake its head in distress and Lucas is now up.

(@Grant: According to the turn order, it's Dr. A's turn, but I can take Lucas' turn first if you wish I guess.)

"No... no, no, this.. Th-that ain't right! Surely I-..." Lucas trails off and looks away, still seeming lost in thought despite the harrowing situation, if but for a few moments more. Then following a sigh, he thrusts out a hand and creating a small sphere made by all appearances to be a kaleidoscope of dancing colors. "You have the right of it! Dispatch them quick as you can, or scare'm off!" He called it the others before barking out a final command phrase, sending the ball of energy gathered streaking for through the astral like a deadly meteor for the same one Corwyn assaulted.

Action: Cast (Cantrip)Chaos Burst at same target as Carowyn.
(Lethal)Sorcerous Burst - Attack: 20 For: 21 Acid Damage. (Originally 15, but since one roll was an 8, I was able to roll an additional die)

(OOC: Accidentally rolled twice for that attack, so ignore that 10 to hit)

Dr A acted - you just don’t know what he did!

Passoveloce is now 130 feet away from the swirling melee that is now the two fish creatures and Corwyn.

Fish #B lunges at Corwyn - 1st Attack - Attack: 12 Damage: Unable to parse dice roll. - 2nd attack - Attack: 19 Damage: 19 - 3rd attack - Attack: 10 Damage: 11

Passoveloce - you’re up followed by Corwyn

"Dammit!" mutters Passoveloce to himself, as he thinks himself to a stop and returns to 45' from the melee, "I guess I'll have to hover and fight, though I do like the thought of firm rock under my feet." 

He fires two arrows at the fish attacking Corwyn (Fish #B)

Attack: 18, damage: 7, Sneak attack Bonus damage: 8

assuming that is a hit, advantage on 2nd attack:
Attack: 24, damage: 10 

Then he stows his shortbow as he realises he will need to pull out his shortsword for the next round.

Action: Attack, Bonus action: Dash (all rolls in game log)

 INT dc15: 13, fail so no dash so only moves to 80', attacks still stand, but does not stow shortbow as will need it again next round.

Passoveloce can only cover 50 feet if he mover his maximum movement. He will still be 80 feet away! As movement on the Astral Plane is a factor of intelligence, Passoveloce will need to make a DC15 Intelligence check to do so!

Corwyn:

Taking a massive bite from the fish creature, Corwyn retaliates by igniting his sword (bonus action to ignite flaming sword) and slashing at it repeatedly!

Green Flame Blade Attack:  Attack: 23 Damage: Unable to parse dice roll. and on a hit the adjacent fish takes 11

Second Attack:  Attack: 23 Damage: 22

Third Attack:  Attack: 19 Damage: Unable to parse dice roll.

(On a miss, Graze does 5 points of damage)

Did Corwyn hit Fish #A or Fish #B

Quote from GrantFromCanberra >>

Did Corwyn hit Fish #A or Fish #B

 (Corwyn is continuing to focus on the same fish he initially attacked, hoping to take it down before it can eat him!  As written, it was the closest one, but I am not sure if that was A or B)

Corwyn’s attack stops Fish #A in its tracks. Fish #B shakes its head in what appears to be pain. Lucas is up!

"Jeeze Louise, these things don't know when to give up! Hanging in there guys! And--Wait... Oh for **** sake, what happened to the--!?" Lucas catches himself mid-sentence as the sight of one of the fish reeling in pain for no apparent reason throws him off for a moment or two. A small part of him half-hoped it might be Dr. A's doing. But leery of the possibilities of being third partied by a invisible assailants, he fishes out a pinch of talc from one of his component pouches, smears it just beneath his eyes, and with the soft uttering of an incantation, his eyes turned into inky black pools before he scanned the area again.

Action: Cast See Invisibility on self.

Bonus Action: Using Observant Feat to Search and scan the battlefield for any other noteworthy signs of other creatures with a 7. 

Lucas scans the horizon and up close. He can see nothing other than the Fish #B attacking Corwyn as the carcass of Fish #A drifting off into space. Meanwhile Fish #B bites at Corwyn - 1st Attack Attack: 27 Damage: 18 / 2nd Attack Attack: 19 Damage: 13 / 3rd Attack Attack: 11 Damage: 5

Passoveloce - you’re up followed by Corwyn

Passoveloce moves up to 30' from the conflict and lets loose with another two arrows from his shortbow into Fish #B before stowing his Bow and drawing his shortsword.

Action: Attack

Arrow 1: Attack: 21 Damage: 9 sneak attack bonus damage: 9

Arrow 2: Attack: 28 Damage: 6

Bonus Action: Draw Shortsword.

(Note: Rolls in game log - forgot to set Advantage for 2nd attack, so rerolled)

Corwyn:

Reacting with another hastily-conjured Shield spell, Corwyn blocks one of the hits, but the other savages the elven warrior!

Corwyn takes a deep centering breath and continues his onslaught, slashing with his flaming greatsword repeatedly!

(One hit taken for 18 damage, bonus action Second Wind healing:  15

Green Flame Blade Attack:  Attack: 10 Damage: 23

Second Attack:  Attack: 13 Damage: 20

Third Attack:  Attack: 23 Damage: 23

(On misses, Graze does 5 points damage)

Lucas is up

Though grateful at the lack of signs of additional threats, Lucas frowned and furrowed his brows as thoughts drift back to Dr. A. "Ah, **** it. He's a grown ass tortle." The sorcerer muttered following a defeated sigh, then once again condensed and raw magic into an acidic orb and flung at the last of the space sharks. "Go on now and get!" He called out as well if the creature somehow survived the attck.

Action: Cast (Cantrip)Chaos Burst at same target as Carowyn.
(Lethal)Sorcerous Burst - Attack: 19 For: 14 Acid Damage.

Fish #B sporting several scars but still active attacks Corwyn - 1st Attack Attack: 25 Damage: 17 / 2nd Attack Attack: 19 Damage: 19 / 3rd Attack Attack: 11 Damage: 16

Passoveloce is up!